Info on contacts?

Well in Gmail there is the ALL contacts, which includes emails that you sent or where sent to you but are not actually in your Concact list. those are not synced up with the droid. other than that, i'm not sure.

 

You can create groups within Gmail contacts and tell the phone to only display contacts from certain groups. This is the best way I've found to managing contacts.

If you hit the menu button while on your contact list, you'll see display options. You can then select your account and under that you'll get all of the groups you have in Gmail. You can turn on/off different groups. As long as the "All other contacts" is turned off, you won't see everyone you've ever replied to.