750GB or 1TB hard drive?

I crippled my late-2009 17" MBP after installing Windows 7, NTFS-3g and Macdrive. I'm not sure what the culprit was, but now the Mac is having issues and trying to repair the disk with the system software CD finds a "keys out of order" error that is not repairable. So I'll be reformatting the disk and restoring it from an recent Time Machine back up.

Since I'm going to be essentially starting over, I thought this would be a good time to upgrade from the original 500GB/7400rpm hard drive to a 1TB drive but I see the latter only exists in 5400rpm at the fastest. My research has come up with contradictory statements. Will 5400rpm be noticeably slower? If so, should I get a 750GB/7400rpm drive instead? Will the 5400rpm drive use less battery power? My original drive is pretty battery-efficient at 7400rpm. Can anyone recommend a model of hard drive? At Newegg, my only 1TB choices are the Western Digital Scorpio Blue (5200rpm) or the Samsung Spinpoint M8 (5400rpm). And lastly, does the cache matter much (8MB vs. 16MB)? The 1TB drives only come in 8MB. I'm clearly no expert in hard drives so any help is appreciated.

Still tough to decide although I'm leaning towards the 750GB. Doing a little more research at OWC and storagereviews.com does recommend the 1TB/5400rpm drives as secondary drives. Still hate to miss out on the extra 250GB of space given the cost difference is only about $50. But since I do 3d modeling and rendering for the most part, it's probably best if I prioritize speed.

Thanks for all the input. I ordered the Hitachi Travelstar 7k750 (with enclosure case so it could have a second life as an external hard drive). I figured the 7200rpm was more important than the 1TB drive that could be slower. I opted for the Hitachi because its specs state it uses less power than the Seagate. However, the WD Scorpio Black power usage is pretty good according to the spec. It's tough to say if the stories about WD are just anecdotal or based on certain usage patterns. Thanks again.