DR. GIRLFRIEND  Nocturne 2 is available from iusethis.com (sorry for the link to an outside site, but Nocturne 2 isn't on the developer's site for some weird reason):

http://osx.iusethis.com/app/versions/nocturne  
(Version 1.0.4)

BRIAN KENDIG  Nocturne 2.0.0 is out, and downloadable from some sites (Google for it), though not from the developer's own site for some reason.  
(Version 1.0.4)

PIZZACAKE  This is an awesome app. The ability to choose different colors for black and white really sets this app apart from others. I always liked using grayscale for general computing however the universal access grayscale is really harsh to look at for a long time. By choosing softer colors rather than pure black and white means I can get the display looking exactly as I like it.

Thanks to the developer Blacktree who also made Quicksilver.  
(Version 1.0.4)

DNEM41  is this the same thing as the Command+Option+Control+8 keyboard shortcut?  
(Version 1.0.4)

GCOGHILL  Cool app, a few comments:

The options only seem to work on the main monitor. Secondary monitor is inverted, but color tint only happens on main screen.

Brightness control didn't work for me.  
(Version 1.0.4)

THECOMPUTERMEDIC  So simple and so nice. Saves battery power and nigh-sight. Easy to use controls and good options.

One suggestion, when switched from day to night or night to day, instead of the screen flashing all white first, have it flash all black. The bright flash in a dark room is jarring and a waste of (minimal) battery power.   
(Version 1.0.4)

BALTHAMOS  Another excellent application from Blacktree. Great for surfing at night when you don't want to light up the whole room. The only thing that I have trouble with is switching in and out of day/night mode. If you could mod + click the menu extra to switch, that would be pretty slick.

Also, if I am surfing and want to look at a picture or text (full color, standard settings), it would be nice if there was a way I could draw a box around that part of the screen, and it would temporarily open a "window" so that I could read the text/look at the picture, then when you click out of the box, it's all back to night mode (think how Preview handles it's crop box selection).  
(Version 1.0.4)

LIKOS  This is awesome! I changed the white color to red, to preserve night vision while surfing. i also decreased the brightness (got 30 min more runtime from the battery!)

i have been wanting something like this for some time. i'm glad i took the time to search last night.

thanks for a great app! (btw disabling shadows does not seem to work. but everything else worked great.)  
(Version 1.0.4)

TOMIS  Definitely cool. Unfortunately the "Invert Hue" only causes display distortion and nothing else. There are a couple other bugs as well. Still needs a bit of work, but it's definitely a good start.

So nice having all these settings in one place instead of having to use a combination of the Universal Access settings, and a program to alter the RGB gamma.

MacOS X 10.4.9 - iBook G4  
(Version 1.0.4)

HEAVY_SHOWER  I really like this little app. And although I prefer this brand new menu icon, I am also partial to an icon switch between night and day—however the previous black sun looked too much like one of those bonus bursts. Regardless, this is a fun, friendly app to have around, even though it won't be used it too frequently. Thanks!  
(Version 1.0.4)