Mac apps I currently can't live without:

Adium
For the working instant messenger - our office has a bunch of ichatters, and a bunch of people on MSN. Adium lets me have the best of both worlds, without having to have two apps and two contact lists running. VERY helpful. How can you not love it if its icon is a green duck? Come on.

DoggieBox
I happen to be dating the guy who writes this app, so since I (ahem) still haven't used it much, love has got to be worth something in this case. But, if you like drums, and like clicktracks, then check this one out. Especially if you live in an apartment and can't record your drums live. Cool folks in NYC have used it to record entire albums - it can't be all wrong (warning - very metal music at aforementioned link. Not my style, but if I recall correctly, guy recorded an entire album in his closet. Impressive).

SubEthaEdit
This is just coool in concept. Now I need a team to collaborate with. In the meantime, I've been using it as my text editor these last few days, and I'm preferring it to BBEdit. Which says a lot.

CSSEdit.
Visual style without the headachey eye-numbing code elements (well, they're there, just prettier).

Transmit
Just about the best mac FTP app I've discovered so far.

iWork
iWork promises to be a good app for me. It's intended to be a time-billing and invoicing application, for folks who are self-employed. I've been using it for about two days now, to do various invoicing stuff for my freelance gig and it's great. Definitely something I will be purchasing. I've also heard good things about Studiometry but haven't tried it yet.

Mental note: tracking mac software. A good list of other apps.