I hate installers. Computer columnists hate installers (http://www.macopinion.com/columns/tangible/99/08/26/). Everyone I know hates installers, except computer programmers.
Computer programmers love installers because it means less work for them and more work for users. Why bother having your program determine the user's configuration and checking what features are available when you can just ask the user! Well, you should bother because the programmer may just happen to know more about what configuration the program requires and what features are available than the user, since the programmer created the program and all.
My pet peeve is applications that require you to uncompress the installer, run it, asks a bunch of technical questions, locking up your computer, and spraying hundreds of files, fonts, extensions, folders, and aliases everywhere before you find out that it actually won't run on your computer. Urge to kill growing... GROWING...!
All applications should be distributed as runnable files. You should be able to run them off a CD after locking your hard drive to prevent the app from writing any files there. If your application requires special fonts or extensions to run, they should be bundled with the application and not installed as separate files.
Installers should be banned.