About battery usage, runtime can vary between about 6 hours to 2 weeks depending on radio and GPS usage.
A few tips I can give you:
1) disable 3G when you don't need it, it sucks a lot more batteries than 2G
2) if you have a huge gmail inbox folder, do not sync it on your phone, that will keep using radios and drain your batteries: set gmail sync days to 0 days so that it syncs on demand or not at all.
3) GPS drains the batteries. Some 3rd party applications leave the GPS on or use it quite a bit. I'd recommend against using those.
4) some other 3rd party apps keep the phone awake and prevent the CPU from going to sleep. This will drain your batteries too
5) Reboot your phone (to reset awake counter), go to settings/about phone/status and scroll to bottom. Leave your phone overnight unplugged from a charger and watch the awake time. I should be in the 5-10% range. If it's not, you have a problem with one or more applications waking up the phone too much or keeping it awake.
Android battery life can be good enough (2 days for me with normal use, including gps/google maps, a few phone calls and occasional note taking), but it's easy for it to go into suck range and hard to see which application is to blame.