Why not both? What kind of money are you looking at spending right now?

You could do something like this; buy your projector used, buy an EP 500 and a set of bookshelves and build your own screen. When you get some more cash, use the bookshelves speakers for your center channel in parallel, and buy the remaining speakers you need for your 5.1.

Good, slightly used Panny 900’s and Z-4’s are always going on sale as the owners are upgrading to 1080P projectors. Many have been professionally calibrated too. And as long as you have a good sub, 2.1 can be quite enjoyable. Keep an eye on this board….
http://www.avsforum.com/avs-vb/forumdisplay.php?f=125

Or here. http://www.digitaltheater.com/

The reason I suggest buying a used projector is that 1080P projectors are starting to hit the streets and I’d wait a year before buying one after the dust settles from the rush to market competition. Plus, by then, the HD format war should be about over, maybe… In a year or so, all the 720P projectors will be selling for quite a bit less than they are now.