Here are some Mac Apps that I depend on every day!

ShoveBox - ShoveBox allows you to quickly store notes and organize them later using drag and drop (or so called "shoving"). ShoveBox has saved my life several times already!

Sleep Display - Really useful for downloading things over night!

Screenflick - Slick and easy to use screen capture

RapidWeaver - Produces amazing websites quickly!

Ecto - Blogging offline for Mac!

Fluid - Turn web apps into desktop apps!

Flame - IP and Service scanner, really handy for SSHing co-workers/classmates so you can *cough* play evil pranks on their Macs *cough*

Dock Dodger - Removes any application's dock icon from the dock

AutoRate - Rates iTunes track based on play count and frequency

Adobe Photoshop CS3 - I use Photoshop so often it's not even funny

InsomniaX - Disables automatic sleeping when you close your laptop lid

TextMate - Amazing text editor for coding

That's about it! Post your favorites in the comments!