I second Jon's recommendation of Other World Computing. Their products have reliably supported Apple computers for many years, and their return policy as well as support is among the very best. Not necessarily the most "stylish" in appearance but always rugged, reliable, and among, if not the, fastest.
Note: I have no pecuniary relationship with OWC other than that of a satisfied customer.
"All you've got to do is own up to your ignorance honestly, and you'll find people who are eager to fill your head with information" --Walt Disney
