I would echo all the sentiments about getting a 256MB card. If you want to game anything new at all, you'll need it.
Also, if you are thinking of unlocking pipes, just go with one tha already has the full complement of pieps already...even if it costs more.
The chances of getting a core that is not unlocked and getting good pipes is almost zero.
The reason those cores are locked in the first place is *because* the pipes are bad. They bin them that way. The ones with good pipes go on the cards they sell that come with all the pipes unlocked, and the ones they sell with some of them locked are the ones that are binned with bad pipes.
You are taking a gamble when you try to unlock a card's pipes, and the odds of getting a fully functioning one are very low.