Not sure. I'd guess a few hundred. I ended up having to merge about 20 profiles. I also deleted about 30-40 contacts that I didn't want.
The biggest problem was that the Exchange sync brought in people with weird Windows/administrator/user listings in their profile. It didn't help that it looks like the admins have left in people that haven't worked at the company in years, but that is hardly Palm's fault.
My plan is to dedicate one of my gmail accounts specifically for storing Pre contacts. That is if I decide to get a Pre.
Tell me more, how would that help you?
Well, I like the idea of my phone contacts syncing online but I don't neccesarily want all of my email contacts nor all of my facebook friends filling up my phone's contact list. So, I will take my phone's current contact list and make it the exclusive contact list on one of my gmail accounts that I only use for recieving non-personal emails. That way I have a copy of my "phone" contacts on my phone and a copy online.