For me, Barry Sanders. I was a Detroit Lions fan before he got there (I really missed Billy Sims after he left) but even were I not a fan, I would have been electrified by his incredible ability. The most fun to watch player I've ever seen (seen a good amount of tape on Gayle Sayers and I think Sanders was more fun to watch).
Second favorite would probably be Art Monk. The guy was class. Great receiver.
Who's yours? For your Euro's who's your favorite football (soccer) player...
Grady