100 watt amps can be very cool indeed, like the Blackheart 100 watt head with six preamp tubes.

As far as great contributing bass players in rock bands, in a few "rock" bands of old the bass players were key players and irreplaceable, at least in terms of the band sounding the same. Three of these being Hendrix's Experience, Noel Redding; The Who's, John Entwhistle; Led Zepellin's, John Paul Jones; and the Stones', Bill Wyman. The Stones, in particular, just don't sound the same without Bill Wyman, in my opinion. Redding, Jones, and Entwhistle had unique styles and were integral to the overall sound of the bands. Of course, Paul McCartney's bass contribution can not be discounted, although he uses a guitar player to play bass in his current band on must songs - a beautiful Gibson SG bass.

Typically though, I would agree that in average gigging cover bands that a lot of different bass players could probably do just as excellent a job in supporting the band.

One thing I noticed in most modern real heavy metal bands, screamo, etc., the bass players and drummers are generally super excellent and super loud and the guitars and vocals sound buried behind their booming rhythm - at least in my observation listening to a lot of the music my son listens to and bands he has been in. A friend of mine has a 2000 watt per channel bass power amp and he uses it in clubs: super loud, including incredibly loud head busting drummer that is proud of breaking a snare head each show. Obviously a lot of people would not want to be in a band like this but you wouldn't believe how many super loyal fans they have. They are called "Farewell Rescue".