Last night, I was playing Betrayal at the House on the Hill which is basically a survival horror game by WotC. And I just got thinking about how that might work with a TT RPG. I mean, there's the whole Hero Clix (which I've never played), and the Mechwarrior TT stuff as well. So, basically, just finding tile sets that work for the sort of game that you're running is the main issue and that'll give your game a lot of variety, if you can GM on the fly. You've got visual representation of cover and distance and all that, but unless you lay the tiles down in accordance with your map, you're running blind basically doing things like the old D&D Random Encounter Tables.
I used a few of my old TT module maps from other games, like a Star Wars D20 map for a game using the little tokens they had for minatures but after a while, a little variety from modules is nice. Anyone got any suggestions on what might make some good options?