Sprint HTC Hero :: How To Manage Google Contacts?

I just joined the world of smart phones and I'm loving my HTC Hero and the Android platform but I'm not understanding all the contacts. I've never been one to keep a very neat & tidy Google contact book (though, I guess it's about time to start), so I'm noticing that now that I've synced my phone with my Google account, I have TONS upon TONS of contacts -- many of which I don't even want in my phone. Obviously, the phone has added my G mail contacts. So now, as I'm adding everyone's phone numbers (something I never kept in G mail), I'm added it to their Google Contacts listing. Is that the best way to do it? I've read a few posts about the topic and I see a lot from people who are previous smart phone users, but what about us newbies? So my question: Is there a way to make it so Google syncs everything *but* my Google Address Book, allowing me to only have my phone's contact list? What about hiding some contacts? If not, what are your suggestions for managing your Google contacts.