GEORGE THE FLEA  I don't know why this is listed on MacUpdate; Espresso is not really in a state yet where it's ready for any but the curious and those who want to develop Sugars. Although the current beta should give you a basic feel for the core features, I would not recommend evaluating it yet as a possible replacement for your current text editor.

Please note that you'll also need to install several Sugars if you want to try it out successfully. Another commenter's problems with PHP files were because at this point in the beta Espresso only ships with definitions for HTML/XML, CSS, and Javascript. I imagine once core sugars like the PHP one are mature, they'll be bundled with Espresso, but right now everything (program and Sugars alike) are very much in beta.  
(Version 1.0b3)

GEORGE THE FLEA  Actually, Mariner just has a deal to distribute StoryMill (which was once Avenir). The developer (Todd Ransom) still maintains complete control over the code, and will be handling bug reports and feature requests just like he did for Avenir.

There's info on this in the old Avenir forums (which I think will be migrating to Mariner Software soon) if you're interested.  
(Version 3.0)

GEORGE THE FLEA  This is a pretty fun little game. Real time-waster. I was never willing to pay the full price, though, since it isn't particularly varied.

A great game for kids, particularly. Lots of marine trivia, and a very engaging and easy-to-pick-up gameplay.  
(Version 1.0.1)

GEORGE THE FLEA  I'm never a fan of WYSIWYG software for myself (being a web designer, and hard-core addicted to writing code by hand), but from what I've seen of it, this is one of the best such editors for people who don't know much of anything about coding and aren't interested in learning.

The downside to this software is that it is entirely template based. The positive part of this is that your site will probably look great if you choose a good template. The downside is that it may well look just like a million other sites. If you don't care about having a look-a-like, then go for RapidWeaver. Otherwise, hire a designer. ;-)  
(Version 3.6.3)

GEORGE THE FLEA  Dang, I wish MacUpdate would quit offering such good software in their promo.

This is another one of those things that seems like it's amazingly useful, but I've never taken the time to really learn it. I will definitely have to download it again and give it a solid try.  
(Version 2.0.2)

GEORGE THE FLEA  Surprisingly, I just reviewed this app; and I loved it. If you want to read the review, here it is:

http://tagamac.com/2007/09/filespot_review/  
(Version 2.0)

GEORGE THE FLEA  I've definitely been enjoying this app. I used iTunes Bar (with Konfabulator, now Yahoo Widgets) for years, and I definitely got to like its thin display and hotkey access. Although TuneBar isn't quite as pretty, it's definitely got the functionality there. I actually just stumbled across the trial recently, and have been very please with the way it will display the track's title in the menubar. (Of course, that won't be very helpful for people who have a really full menubar.)  
(Version 2.7)

GEORGE THE FLEA  This is an amazingly useful utility. I've been using the free version for months (maybe even years).

My favorite feature is the date hover that shows up when you mouseover the time. So much quicker than having to click the darn thing.

I haven't seen the OS default clock in a very long time. The price was always too high to justify the extra features, but this deal pretty much seals it as far as I'm concerned. Good pick, MacUpdate!  
(Version 2.7.3)

GEORGE THE FLEA  I was sorely tempted by ZigVersion awhile ago. This is a piece of software that is a well-designed front-end for powerful versioning software, and easy to use and learn. I was turned off by the hefty commercial license, though (since I'm designing commercial websites, with no fronting capital really).

However, this price is very tempting. The only reservation that I still have is that the upcoming Versions from Made By Sofa looks like it might be a competitor worthy of supporting. On the other hand, it isn't out yet and Made By Sofa sometimes charges quite hefty prices, so who knows.

In any case, this is well worth checking out if you use Subversion, or want to use it but are put off by the command line interface.  
(Version 1.2b3)

GEORGE THE FLEA  Meh, tried it a while ago, but I'm not sure this one is really worth registering. I'll have to give it another shot and see if my first impressions were off.  
(Version 1.15.3)

GEORGE THE FLEA  To respond to an earlier poster: Backpack has a free version, but it's not free. There's a monthly charge if you want any sort of storage or a web calendar.  
(Version 1.3)

GEORGE THE FLEA  Ha ha, I used to love Bugdom 1. I wonder if Bugdom 2 is as good.

Of course, the ants always totally kicked my butt. It was a little embarrassing.  
(Version 3.0.6)

GEORGE THE FLEA  Is this even compatible with CS3? Is there an Intel version?  
(Version 1.3.2)

GEORGE THE FLEA  I've heard really good things about this app. I tried it once upon a time, but decided finally on going with EagleFiler, since I prefer a transparent storage format over a database. On the other hand, I believe DevonThink has a far superior search algorithm.  
(Version 1.9.9)

GEORGE THE FLEA  I have to admit, this does look like a nice little utility.  
(Version 1.0.2)

GEORGE THE FLEA  Definitely a very useful program, and you can't argue with 40% off.  
(Version 1.1.2)

GEORGE THE FLEA  Although a nice-looking product, I'm not really sure if KIT could replace EagleFiler for me; I'll have to keep playing around with it.  
(Version 1.3.5)

GEORGE THE FLEA  Haven't used Celtx, but one thing that springs immediately to mind is that Avenir is intended primarily for fiction; Celtx is billed as screenplay writing software. I suspect that if you try the two pieces of software you'll find they are suited for very different kinds of writing.

Definitely give the 30 day trial of Avenir a whirl; it should give you a very good idea if the program works for you.  
(Version 2.3.3)

GEORGE THE FLEA  Ferruccio:

You can create your own project-wide notes by creating a new generic view (in the views pane, select the gear->Manage Views...). Put an item with your project-wide notes in this view, and then double click the item to open it in their own window. Stick the window off to the side somewhere handy, and voila: project-wide notes. You can also have multiple items in the view, of course, which is more useful than a single project notes field, IMO.  
(Version 2.3.3)

GEORGE THE FLEA  Scrivener is well worth looking into; it is some of the best writing software to come down the road in a long time, and a beautiful implementation of the index card organizational scheme.

In my opinion, however, Avenir is better suited for fiction thanks to its focus on things such as actors. If you write fiction, you should definitely give both a try.  
(Version 2.3.1)

GEORGE THE FLEA  I bought Avenir back in version 2.2 because, although the interface was klunky and it didn't have all the features I wanted, I liked it better than CopyWrite and the developer said that he was adding tags in 2.3.

I used 2.2 a bit, but not extensively. Version 2.3, however, has turned this program into a serious contender with other writing software. As far as I am concerned, Avenir is my single most important tool as an author. The implementation of tags as universal metadata, the no-frills fullscreen, and the powerful scenes-centric organization make Avenir perfectly suited for writing fiction of any length. I am currently half-way through a novel that has been written entirely in Avenir 2.3 and it has been an incredibly pleasurable experience.

I have been actively beta testing 2.3, and although Avenir is stil missing some important features (like versioning), the developer is extremely open with users and takes user suggestions and criticisms very seriously. The fact that Avenir is still being actively developed and that the developer is willing to implement user-requested features makes this software a pretty incredible value if you are willing to actively participate in the community.

One thing to note is that Avenir is not software for everyone. If you write fiction, you may well find it indispensable, but for general-purpose writing a tool such as Scrivener may serve you better. On the other hand, the reliance on tags allows for a great deal of user-defined structure within Avenir, and the interface is simple and easy to understand (whereas programs such as Scrivener suffer more feature bloat).

I really cannot recommend Avenir strongly enough. If you write fiction, you owe it to yourself to give this software a try, and if you have any questions about it please stop by the forums and find out for yourself how helpful the developer can be.  
(Version 2.3.1)