I'm a senior this year, and will (hopefully) be getting a new computer for school. While the ability to boot into windows seems very useful, I think that I could really use the grunt of a PM G5. I know there's no way i'm getting the Quad, and the dual 2.3 seems a tad bit underpowered for a brand new computer in a line that hasn't been updated in a while. What would you think of getting a used Dual 2.5 or 2.7 instead? Where/about how much would these go for? I'm looking for a retailer since my parents would be involved in the purchase (I.E. Ebay is n/a). Any great links I haven't found out about or advice concerning my options?