Alot of people delete, VZ Navigator and Visual Voicemail. Also by clearing your event log every once in a while will free up your memory.
Not sure how much room this gives you because it sort of depends by device. Everyone has different 3rd party apps installed and running, so it's basically trial and error...
I think weatherbug is an awesome app, but kills the battery and memory and generally jams up the phone. Phone was definitly better after getting rid of it.
Some of you have memory and storage (i.e. -hard drive) space confused...
The memory issues people are posting about is reference to the phone's "RAM" space. Not the ability to store apps. The more apps you have open/running at one time, the lower your application memory will be, making your phone run slower. If you notice right after a battery pull, most of the time, your memory will go up. This is because some of the processes are not running, not because you have deleted an app...