I'm sure there is more factors involved and it wont make a huge difference but for the most part which is more important for gaming? (running windows 7) for example a 500gb 7200rpm 16mb cache hdd vs a 2Tb 5400-5900rpm 64mb cache.
10,000 rpms is better but then again you have heat and PSU requirements. I use 7,200RPM either 16MB or 32MB cache. 1TB or higher users larger cache as large as 64MB. But don't buy those Green HDD they're slower and to be green and save power they spin slower. 7,200RPM is much faster less wait time. But you give up green features. The large cache just holds more I/D before it's needed. So best to use a fast spinner than a slow one.