In 2000 (my first year in the competition) I remember a few bots worth mentioning.
Team 19 - Big Red, they built an amazing turreted arm that could hang from the bar, and was also useful in "swallowing" balls to be scored later.
http://www.firstrobotics.net/00gallery/019-1.jpg
Team 15 - Coqui Power, they squeezed the balls up through the bars of the troughs. It was an amazing little bot that darted all over the field (and under the bar) with ease. Now maybe this was done earlier on (98 maybe?) but this is one of the only bots I know of that slowly compressed balls and squeezed them into goals.
http://www.firstrobotics.net/00gallery/015-1.jpg
2001-
Team 111 - Wildstang, I'll never forget the first time I saw their "teaser" video. I never even thought of being a "ramp-bot".
Team 151 - Wildcards, They had that great autobalance. There were only a few teams that did it, and they were definitely one of the best.
I really wish I'd been in this competition for longer. (it seems like I can think of more innovation in 2002 than any other year I'd been involved, but alas... I can't post those till next year).