Your best bet is a CRT, any 32" is good. Just avoid Sony Trinitrons. They were the best, but now they're all broken. Whatever you find, test it before you buy it.
If you want a flat screen, get a plasma. They have the best contrast ratio, which is what you want for gaming. They are also the cheapest, which is nice. Just bear in mind that your SNES will look like horrible garbage on any flat screen. 240p is in no way compatible with an HDTV.