Textmate

Both Arne and I are avid Textmate users, and most of iusethis has been coded
in it. I really love how easily I can navigate, both with apple-t (Go to file) and it's autocomplete, and by browsing the project drawer. The project wide search also often comes in handy.

As a perl programmer, I also often use ctrl-shift-v for validation. Being able to see that my code is well formed easily is very time-saving. I haven't quite learned all the various key
combos yet, but apple-ctrl-t lets me easily find the function I'm after. There's lots of useful built in functions like an online paste service, svn and svk integration, and code templates.

Textmate also has several useful plugins. I've registered the ones I know of on iusethis, under the textmate tag.

All in all, Textmate has been a huge help for me when coding iusethis, but as I understand it's also quite useful to web designers. I'll try to get Arne to do a followup post on his favorite functions :)

*update* There is one tip I forgot to mention, something I use a lot. I've set up QuickSilver to index the Source folder in my homedir. That way I can open one of my projects directly from quicksilver, by selecting it and using 'Open With' 'TextMate' . Then it comes up ready as a project. This lets me context switch really easily.