Help me buy an XBox.

OK youze guys, after hearing about Microsoft's GDC keynote and its plans for XNA, I'm hot to buy an XBox. I mean, I kinda have been for two years, but I can more or less afford it now, and my justifications have never been more solid.

I understand (with Wikipedia's help) that it currently comes in three sizes, and that (correct me if I'm wrong) I want the middle-weight "Premium" one, versus the "Arcade" or "Elite" ones. (Sigh.)

What on-disc games that are available right now should I get? (Fritter me not with your talk of pre-orders.) What downloadable games should I get? Assume that Portal and Rez are already in my imaginary cart.

Any other things I need? Extra controllers? Who what?

I'm just going to play it on my old crappo TV for now. Yeah, I know.