VERYVITO  Been using this forever now, and can't understand why anyone would use anything else. Absolutely fantastic utility that requires zero effort on the user's part.  
(Version 1.1.4)

DSPENCER3491  I find the whole concept of this utility to be much more attractive than other applications that delete associated files with the application. It's very convenient because all you have to do is delete the application and it asks you if you want to remove the files associated with the program which makes it more convenient and productive than having to open up an application like appzapper every time you want to remove something.  
(Version 1.1.4)

JOZGTA  Excellent utility. I'm using it for a while now (6+ months) and it has always worked flawlessly. There are other good utilities out there (sometimes also free) that do more or less the same. Have tried a couple but prefer this one because it is simple (no unnecessary bells & whistles) and it runs in the background; I don't have to launch anything before I can safely drag an application to the waste bin. Big thanks to the developer!  
(Version 1.1.4)

LOCUTISOFBORED  Installed over older version using OSX 10.4.11. Now I get the Preferences Error "Could not load AppTrap preference pane." What a pane. Am I the only one experiencing this?  
(Version 1.1.4)

FORMICA  I have tried AppTrap, and it's OK. However, when compared with AppCleaner 1.2.2, the difference is STRIKING. AppCleaner does most of the things that all of the reviewers below ask for, it finds ALL of the files associated with the main app you are deleting — EVEN FILES THAT ALL OTHER SUCH APPS OFTEN MISS — it is totally unobtrusive and doesn't impact your CPU or memory AT ALL as far as I can tell, IT WORKS AUTOMATICALLY when you maybe forget to startup AppCleaner and just toss an app into the trash ITS SmartDelete CATCHES IT AND ALSO AUTOMATICALLY CATCHES ALL ITS ASSOCIATED FILES AND OFFERS TO TRASH THEM FOR YOU! And perhaps most amazing is that it is so superior to all other such apps but it too is FREE, FREE, FREE, FREE, FREE! If you don't believe me, just check out the comments and reviews on AppCleaner's MacUpdate.com (http://www.macupdate.com/info.php/id/25276) and VersionTracker.com pages (http://www.versiontracker.com/dyn/moreinfo/macosx/32740&mode=feedback). That level of user satisfaction is far, far higher than all other such apps, illustrating that people love it for all its capabilities and performance — not just its price (which, again, is FREE!).

When you try AppCleaner, set the preferences to "Protect launched apps," "Protect default apps," and "Enable 3D transitions," don't forget to turn on SmartDelete, then one-by-one select the "Applications," "Widgets" and "Others" icons at the top of AppCleaner's main window, and with each one select the "Options" menu (in the Menubar) then "Select All" to instruct AppCleaner to protect all those apps, widgets and other resources from being accidentally deleted, then you can uncheck one-by-one all the ones that you don't want AppCleaner to protect. Trust me, you'll love this app with it set this way! Enjoy!

(Oh, and BTW, I am in no way affiliated with the makers of AppCleaner — I don't even know them. I just LOVE IT when truly great software is made available for FREE, and I feel such magnanimous developers should be promoted whenever possible, even when it's a bit annoying (as this comment is because it's in another app's MacUpdate space).  
(Version 1.0.5)

DNELSON  Developer, can we have an update?  
(Version 1.0.5)

RGMENKE  Like many OS X users, I've lamented the lack of a deinstaller built into the OS. From the beginning I've used Deinstaller to remove demo or no longer needed apps. The process worked as long as pkgs were installed, otherwise they don't appear on the list. Then I stumbled upon AppTrap. Wow! Apple should pay the developer for the code and implement it now. The program loads as a Preference Pane an that's it. Anytime you drag an application into the trash AppTrap locates the associated files and deletes them as well. What could be easier?  
(Version 1.0.5)

JEFFNE SCHELIN  The best uninstaller in my opinion. Doesn't requires me to launch it at all. Big up to the developers.  
(Version 1.0.5)

GARRYCH  Nice tiny util. Very helpful  
(Version 1.0.5)

KZX72  This program (not Cleanapp, Appzapper, Appdelete etc) is the uninstaller Apple forgot...

Keep updating it!  
(Version 1.0.5)