Currently you do not need a great or even good computer in order to play the game. You can play it just fine on a decent machine on low/medium graphics. The big helper here is that they don't actually have AA implemented yet because it was causing crashes in the beta.
If it's anything like WoW though, they will be doing graphical upgrades with each expansion, and I'm betting that they're going to aim to throw a good expansion around the same time that WoW releases MoP in order to prevent a huge decrease in subscriptions.
I HAVE noticed actually that the game works better with older Nvidia drivers, particularly the 275.xx release. I had about a 10-15 fps jump when I rolled back my drivers.
---------- Post added at 11:24 AM ---------- Previous post was at 11:21 AM ----------
Correct. I personally want to know when we are cut off from playing with the pre-release. Do we get to play through the 20th? Or are we going to be cut off at midnight and then have to wait for the stores to open in the morning to play again? It seems like a lot of places aren't doing midnight launches for the game either, because of it being the last week before christmas (they don't want christmas shoppers coming in at a midnight launch) and also because of most colleges having final exams.