Lol..let me give you guys some heads up on facebook for Nexus One..I'm a moderate user and have lots of contacts..
The Nexus One has one of the most dynamic ways of handling contacts. This is what you can do:
1. Add your google mail account to your Nexus One
2. Add your facebook account to your Nexus One
What the Nexus One will do roughly less than a few seconds is, it will download ALL your contacts to your Nexus One..What it does, it downloads the facebook profile pic of your friend as the contact's picture.
Now, what you guys must be thinking "I don't want ALL my contacts. My Google is messed with weird emails etc". You don't have to worry about that. There is one checkbox in the contacts which after ticking it, only contacts with phone numbers will be displayed (as in my case, my gmail contacts were now "hidden" and my facebook accounts were listed for those who had included their phone number on their facbeook profiles).
Now, what about the others who didnt insert their phone numbers in thir facebook profile, but you have their profile? No problem..Just create a new contact with the same person's facebook name, and add the phone number to it..Once you hit save, you will realize it did NOT make a new contact. Why? Because it combined with the facebook profile automatically. The person who was not visibile just now, is now visible because you added a phone number

And what about those who don't have facebook? No problem. Just make a new contact and you will have it there

Whats even better? Once you have settled this once, it automatically synchronises to the facebook and google server. So when your phone is reformatted or whatever happen, just add you fb account and gmail again, and there you go..its all there

THAT my friend is the BEST way to utilize facebook for me until now..Even friends of old ages added me on facebook and my nexus one helped getting their number too

not so sure about the gmail u talking about but recently facebook let iphone user sync contacts with fren list too