What would give me the most bang for the buck? I was hoping to get in under $2000, but I may be dreaming. I know there are a lot of good deals on 2009 and 2010 models. But not sure by the time you upgrade, if you are not at the cost of a new one. The main difference might be six, eight or 12 cores in an old one vs a 3.7 Ghz four core 2013 for $2999.