Welcome Aboard!
Are you going to have it RGB modded and use something like a Framemeister to upscale to the LCD? If so, I'd invest in a modded Duo (any version, cheapest deal you can find) rather than spend so much money on a CD-less SGX. If you're going to stick with composite, a SGX wouldn't be a bad idea, though it's quite a bit of extra cost to gain access to only a few games.