Marshall was the best. When he was with the Broncos, Kyle Orton started a season 6-0 by simply throwing short passes to Marshall and letting him run over people to get the first down. He was unstoppable.
Marcus Robinson was also incredible. He had a 1400 yard season with Cade McNown and Shane Matthews lobbing him the ball. I remember he didn't do much aside from that season, but a few years later he resurfaced with the Ravens. The week prior the Ravens had lost to the Dolphins 9-6 in perhaps the worst "offensive mind" coaching matchup in NFL history (Wannstedt vs. Billick!!). The next week with one of the worst starting QBs in NFL history, Anthony Wright, the Ravens put up 44 points on the Seahawks by simply heaving the ball to Robinson (7-131-4).
My personal favorite was Jeff Graham. Not all that big or fast, but great hands and could always get open. The Bears messed up by not keeping him around longer.