I have replaced the standard hard drive on my MacBook Pro (2009, v5.1) with an Intel X25 SSD. The improvement is amazing: The MBP is much faster now and starts almost as fast as my MacBook Air. Check the videos! Start up:
Fishmarket in Seatle. Taken with a Canon 5D Mark II and Voigtlaender Ultron 40/f2 at 1/40 sec., f2 and ISO 250.