There are the obvious - Geddy Lee and Chris Squire, because of their intricate parts; Kim Stone of the Rippingtons and Stu Hamm, because of their groove and mastery of various styles; then there is Gene Simmons - not flashy, not a "master", but a very solid foundation player. I think I really wanted to play bass the first time I heard "Cold Gin" from the first KISS album. That and "Roundabout".
Dave