My first car was bought for $5,000 and my parents put $1,000 down for me, and I was darn grateful like you wouldn't believe for it. Regardless of how rich I ever become, my kids will still pay for their cars themselves. I learned so much about money and responsibility by paying for my car. It actually was cheap education when you think about it.
On to the topic at hand, as I said in other related threads, it depends on a lot. What will your driving habits be? If you have to drive often in stop and go traffic, a manual might be more hassle than its worth. Also, it depends on how good the manual and automatics are. Good automatics are better than bad manuals, and vice versa. Luckily current GM manual and automatic transmissions are decent at worst and darn good at best, so you can't really go wrong either way I think. GM has historically had among the best auto trannies, but their manuals used to be sub-par. From what I hear recently they really improved. Also, I agree with the general advice of regardless of which one you choose, learn to drive manual on some beater car. You never know when the last good rental on the lot will be a manual transmission.