6 hours is a lil above "average" with heavy usage. that's implying that you talk, text, surf the web, surf the market, try out 100 apps (like me). there are a few things you can do to increase battery life, but if someone tells you that they get 2 days with heavy usage, they're either lying or they have the battery of youth.....that's a joke.
there are a few things you can do to increase battery life, but you probably know them already. ahh.....what the heck.
1. turn your gps off when you don't need it
2. set your sync to a lower setting (2 hours instead of 1) or just turn it off. you can manually sync.
3. turn your brightness to manual and set it to the lowest setting.
4. make sure your bluetooth is off when not needed
these are all no-brainers and can be easily done with the system's built in power control widget. in my opinion, it's the most useful widget the droid comes with.
i deliver pizza a couple days a week, so i can tell you that on those days with a full charge at 9am, i can go to work at 4pm and listen to pandora radio, have a slide show running, and use about 45 minutes of talk time and i'll need to plug up at around 8pm. that's with brightness at 100%, no gps, no bluetooth, no sync.
hope that helps