Essential Mac Applications
long list of useful stuff, plus some more ideas in the comments section
FuzzyDave: I wish i could vote 20 on this link. I found it extremely useful.  
thanks so much for posting it.
it's been a pleasure
texasshat: Butler  
Very useful once you customize it. A little toolbar that sits along any side of your screen.
soma13: I'm glad that I already have some of those apps, but there are lots of others there that I can't wait to download.  
Do any of you know of a good site that lists firefox extensions that work with macs/os x? I'm tired of installing firefox extensions that don't work for me. :(