Refurbished iMac

I am trying to decide between a new 17" iMac or a refurbished 20" iMac. Biggest difference in performance is the ram. New 17" has 1 gig and Refurbished 20" has 512mb I am thinking it'd probably be cheaper to get the refurbished 20" for the around the same price as a new 17" and just add more memory. It'll still be cheaper than a new 20" with 1 gig (on a budget). Any opinions or suggestions on what brand ram works the best in Macs?

Bigger is always better . If you don't think you would have a problem upgrading the RAM, why not go with the 20"? It has slightly more processing power, a bigger hard drive and a bigger screen. If money allows, that's what I would go with.

I have always relied on Crucial ram. but Im taking a guess if you use Corsair or Kingston ram will work just as well, but DO NOT get the value ram of any of them. I've made that mistake a few times on a customers system and had nothing but problems.