I'm not sure how many of you go back that far... but does anyone remember X-com. It was a game where you investigated alien landings and eventually have to thwart an invasion. It was turned based, had shooting, line of sight, destructable objects to obtain line of sight, psychic powers etc.
With all this talk, I think it would do a great shadow run in terms of capturing mechanics... but I'm not sure that sort of a game would really appeal to the ADD attention spans of the majority of todays gamers.
Wow haven't thought of that game in ages.