Go cheap, but don't go absurdly cheap. Saving $10 by going with Bob's Discount Ram over a brand you know and can trust isn't a great idea. You don't know if you're going to need a warranty or not until something screws up (like getting a stick in the mail that fails to run at stock speeds for whatever reason), and when that happens, you'll be really glad you've got it.
Kingston, OCZ, Corsair, Mushkin, and G.skill all have very nicely priced value ram along with warranties to back their products up.