OK title says it all. So what is your expierences?

Personally its using the built in browser to get on the internet. lame I know. But I am just getting around to committing to the funtionability of the phone.

I have read where people used their phone as a GPS device. And where others used it an an MP3 player. But I lack the know how at the moment. SO once you list what the coolest thing is, tell a little more about it for my sake and possibly others as well.