Fine
The best thing to look for in video cards in actual performance. Memory size means nothing. Any card can be crammed full of RAM, but be much weaker than previous generation cards.
Sites like GPUreview give you a good idea of the different specs on the card. You can get a pretty good idea of a card's performace by it's fill rates and what not. But still, benchmarks in games are the best indication of their power.
Eh...that's a bit for you. Check out gpureview some more, they have tons of definitions and all there.