Dunno offhand, but my little Samsung RC512 (bought a close-out model last year) has held up very well so far. Funny thing is the model said it could only do 6GB, but I have 8 happily running on the box. 

Since last July, I've only experienced a blown HDD (I tend to work them a bit hard), but otherwise it's worked quite well.

 

Meanwhile, I'm saving my pennies for a MacBook Pro. 

(Now if I could find a decently-priced laptop with a Core i7 and was easily Hackintoshable, I'd just go that route... :) )