played the tropico 3 demo on xbox a while back, it was pretty neat. it was a demo so i didn't get super into it and i'm sure there's alot more to it, but it was enjoyable enough.
i also bought From Dust a week or two ago because i'd been looking forward to it for a while, but honestly it was pretty disappointing. it just "feels" weird and i had a hard time getting into it....then i got stuck on a level and Deus Ex came out so i haven't touched it since. i'd wait for it to be just slightly cheaper, but that's just me. also, i wouldn't get it on PC unless they fix all the things that everyone was complaining about (draconian DRM, bad mouse support, some other stuff i think...i dunno?) with that version