I setup my FB acct (and Google acct) as soon as I booted into 2.1 for the first time. I've tried removing the FB account, adding it back, rebooting in between, etc with no luck.
I have both "Facebook" and "Facebook for HTC Sense" enabled.
It takes my username/password fine, 'sync contacts' is checked, and it claims to sync just fine. When I tell it to manually sync, it 'runs' for about 2 seconds before saying sync complete.
When viewing a contact and sliding over to the updates 'tab', I try to link with their acct but my friends list never loads. Trying to search in it does nothing. Even when I try to view all updates in People, it shows nothing.
The Facebook app and Facebook Phonebook folder work great, but I really want to merge contacts again so it shows their FB pic automagically.