Looking to upgrade the 160GB in a just-out-of-warranty Macbook Pro. It was tough shrinking down from the 250GB on the iMac when I made this my primary system, and now that I've been teetering with 500MB of free space for a while I'm finding it downright impossible. So the ultimate question... 5400 or 7200, 8mb cache or 16mb cache, 320gb or 500gb? I'm leaning toward the new Seagate Momentus coming out at 320GB, 16MB cache and 7200RPM. Desktop performance doubling my storage space for $180. This drive is backordered everywhere for 2-3 weeks (which isn't really a problem), and I'm not sure if I should get the model with the G-Force Protection (only slightly more expensive) or not or even for sure if it'll fit in the Macbook Pro. But, is the performance significantly better than a 400 or 500gb Hitachi running at 5400RPM for $250, or on the other end, a 5400 WD Scorpio 320GB for $130 or so? Are there any better deals out there that you guys know of?