Let me suggest a different tack.
Along the lines of those recommending not spending any money yet and testing systems. If you can, I'd spend at least some of the game time taking a tour of sorts using the free test start systems available.
I don't have a comprehensive list of links, but I think there is one.
I'd start with the ones that have boiled down quick start rules.
Chaosium has a great new one for BRP with adventures.
Pinnacles Savage Worlds test drives are also really good.
I'm partial to GURPS and it has a free subset of rules and adventures.
I'm also partial to D&D 4e and it's quick start. I think it has already been mentioned.
There are probably a lot more. I think white wolf has a few for many of their games. They have them at some game stores, I got the hunter quick start free at a FLGS. (by the way, any white wolf guys, great idea, and thanks!)
After that more fully fleshed out free online systems like the Pathfinder beta, the SRD, Ars Magica 4th (right?) and FUDGE/FATE are all free. Including what was already mentioned, OSRIC and the other old school alikes.
I'd also suggest going to a Free RPG day event,
Free RPG Day. A list of stuff that will be available is at
Free RPG Day Retailers I see a C&C quick start on the list, which is new to me, as well as a couple others including the 'introduction to Dragon Warriors'.
Finally see if you have any 'living' or organized rpg's in your area. D&D 4e RPGA is proably the biggest, but there is the Paizo organized play that is current 3.5, and the Blackmoore one, which until they ramp up their D&D 4e is still 3.5. There are others, I think Rokugon is one that gets some traction around my area. I'm crossing my fingers for MGTrav and GURPS organized play, but those are still rumor mill fodder, for now.