I usually keep like $25 on my card to make the company happy.
I got my car loan with GMAC banking. Really great rate (6.9%). But it is only a Cavalier, but its still mine.
I don't plan to buy anything on this unless it is needed (like new brakes) or for school. My sister worked for Discover for about 7 years. She keeps getting at me to get my credit report, I really should.