I've been thinking about upgrading my current 500gb 5400rpm WD internal HDD for something better in time for Lion and I've been a bit indecisive about my options. My current hardware is an early 2008 Macbook Pro (Core 2 Duo Penryn) with 4gb of RAM (I've got another 2gb coming my way once I heard that the max capacity is 6gb on this MBP). At the beginning it was a case of size so I was considering a 5200rpm 1TB drive but the more I think about it now, I've decided that I would rather go for speed instead (since I do a lot of graphic intensive stuff for my degree). Since my MBP is of the classic variety, I've been a bit hesitant in taking the plunge for fear that it might not work out given the dated hardware. So now I've taken to the Macrumors community in order to make the final decision. I've narrowed down my choices between a 750gb 7200rpm Seagate Momentus and a Seagate Momentus XT 500gb hybrid. Are the differences between the two huge and is the XT worth the extra dough on my hardware? Does it even work on my hardware or am I just better off going for the 750gb with a larger capacity? Any help on the matter will be greatly appreciated.