I need some help. . . I want to replace my completely filled hard drive with a new one. (640 GB 5400rpm Western Digital) Is t...

Ok, now boys lol I have a good sense of humor, I got the idea. So, I guess my next step is to check the price of an enclosure. A few more questions, I read different articles about speeds, Is there a big difference between a 5400 and 7200? Most articles say no, but I wouldn't mind other opinions. Do I need to buy other parts to go with the enclosure? It never hurts to have an extra HD around. What size is the HD for the A1226 (Santa Rosa)? Will the Firewire SATA HD enclosure on iFixti work? When I install the new HD, do I install Snow Leopard first then activate my most recent TC backup? I appreciate all your help, I know how to use a computer =) but not the tech stuff.