I think you need to start over because your address book is already filled with all your FB contacts. If you completely delete your FB account (settings> accts & sync> Facebook> Remove Account), it will clear out the FB contacts on your phone.
Now you can do one of two things.
1) Go to the market and download and install the FB app. When you run it, select "don't sync with contacts". This way, you'll be running FB, getting all notifications, etc. but it won't be linked to your contacts. You'll need to manually add in the FB contacts you want.
2) If you do want FB linked to your phone, then add your FB account under settings "Accounts and Sync" Then just make sure you select to "link with existing contacts". That way, when Facebook Syncs, it will only sync with contacts you've added to your phone.
With either method, you won't have a gazillion contacts show up when you're trying to text or email, unless you have a gazillion FB contacts in your address book
Personally, I switched to option 1 above.
Let me know if this fixes things for you.