The Origins Award is the big industry insider one.
The Diana Jones Award is probably the most influential critical award (and the winner always comes with reasons why they won, hence linking to their website).
The BoardGameGeek Golden Geek Awards has an RPG sub-section.
These three are notable outside the RPG industry.
Hanging onto Wikipedia by the skin of their teeth are the Indy RPG Awards and the ENnies. (The ENnies are far the larger of the two.
Then there are local con awards, of which the most famous in America is the 3 Castles Award (I'd argue Lucca is bigger but that's not in the US).
And finally a whole lot of small fry few people have ever heard of.