KITMOS  Tried to run Weblight but get a message (on June 20th) that it expired June 19th 2010. I had never tried it (too my knowledge) before.  
(Version 5.0.14.2)

MACSOLU  --

Crashes on launch if set @ 64-bit mode (which is the default.) Works fine if set to 32-bit mode. Mac OS X 10.5.8, Mac Mini (2009).  
(Version 5.0.12)

FCHARLY  The v5 update brings a much nicer interface and, among several neat improvements, it checks CSS as well. The author is very responsive to any comment or suggestions. I highly recommend this app.  
(Version 5.0.1b)

NCIANCA  I have been using WebLight for 6 months or so and find it to be a great tool with a number of useful tests. I have run WebLight against complex sites, in some cases with thousands of pages and urls.

The ability to setup rules for checking url's, defining different user-agents, and having different starting points allows you to test the specific portions of the site. With huge sites those features save us a ton of time.

You can also save the reports as a tab delimited file, which can then be imported into Excel, a database, bug tracker, etc.  
(Version 4.0.10)

CF29  This software does a great job. Any conscientious web developper should rely on it.  
(Version 4.0.8)

KLONDIKE KID - ALASKA  Well, you got my vote. As a web designer since '95 and maintaining nearly a dozen sites with several thousand links, I can say all those mysterious, nigh undiscoverable, broken links causing tens of thousands of 404 error codes in my stats each month are HISTORY in 15 minutes of use of Weblight. They will get my money once I've done a bit more field testing and the beta goes gold.

Right out of the gate I began using the program without even referencing the help section. Very intuitive and Mac-like logic. Using the latest Transmit 3.0 version just released (allowing editing html pages right from Transmit menu) and Weblight I bounced back and forth between the reported bad links and the web pages correcting the problems in short order and moving on to the next.

The price is a bit on the "premium" side but any SERIOUS webmaster will appreciate this software in the first use. Finally I don't have to take my URLs to 3rd party Internet site link checkers for their cryptic (and slow) results. This one is a keeper folks! Am running Weblight on a G5 Dual with OS X 10.3.7 and works flawless so far.

Kudos to the programmers for a home run! And thanks for allowing unlimited URL checking on the beta. I checked almost 2000 links online with a 56K dialup in about ten minutes flat.  
(Version 4.0.3)