All new drives in the same class perform nearly identical.
A top-end SSD is much faster than a hard drive but costs a lot more. Some people buy an SSD for Windows then install their games and media to a second hard drive, like this:
1) OCZ Vertex 3 120GB (Windows and programs), and
2) 1TB or 2TB Western Digital "GREEN" hard drive (games, media and backups)
...back to Hard Drives:
If you want a good drive for Windows get any newer 7200RPM drive such as http://www.ncix.com/products/index.php?sku=57432&vpn=WD5002AALX&manufacture=Western%20Digital%20WD&promoid=1367
**Note that NCIX even has the speeds already listed at the bottom.
The 1TB drive (930GB) stores 2x the data for a little more money but there's no point buying it if you know you won't use it.