The two most used apps I have are touchdown --which is not actually about football but is rather email and calendar integration and circle launcher, so I can hide a bunch icons under one and keep my phone screen kind of clean.
I also use pure calendar and juice defender.
Those are all kind of boring and utility related. I also use spotify (music) tapatalk (forum software, though unfortunately, not for this site) and Poynt. Just because I can never decide what I want to eat for lunch so I look to see what's nearby.