Any 2.5" SATA drive should work fine. One standard trick to get a speed bump is to replace the current internal hard drive with:
* a faster RPM drive (replacing a 5400 drive with a 7200 drive, for example)
* a hybrid drive (a traditional hard drive with a large cache)
* a solid-state SSD drive
You can then take your larger traditional hard drive and swap it into the optical drive bay with an appropriate mounting bracket. This gives you the speed advantage of the faster boot drive, with the storage space of a traditional hard drive.
[product|IF107-080|Unibody Laptop Dual Drive]