I think if you had the extra cash, by all means go for the Rev. C model. I would say at least 1~1.5GB or more RAM, depending on what apps you would like running( e.g. motion ). The more the merrier IMO. Do a quick search on eBay to check out the market price, but do try and get rid of it before the 1 year expiration date. Having Extended warranty can add tremendous value to your computer as well cause PB part/labor is quite costly.
Cheers~