Not to be contrary, but I have to add that music is music -- above the 5th-fret, below the 5th-fret, with many notes or few, loud or soft, slap, pick, tap, plunk, crashing through the drums . . .
I think Jimmy Johnson is awesome for exactly the reason that you point out, Duncan -- the man knows how to lay down an incredible groove w/o stepping all over everything. Blows me away, and is EXACTLY what works for James Taylor's stuff (which I love!!).
And I totally agree w/ the general sentiment that a better player knows when not to play, and someone who's not so good could often sound better by just paying more attention to their fellow musicians and less attention to how many notes they can fit into the next bar or two.
But I think folks can get little dogmatic about this type of stuff sometimes too. I like the bigger picture of music; a picture that is a little more experimental and open and pays less homage to one particular genre or another. I know on the average night I probably play too many notes here or there, and I strive constantly to be self-critical and find that more elegant, artistic expression of my ideas.
IMHO though, music is not a platonic ideal that we can only hope to find. Music is a place, a space, a conversation, an amazing auditory experience of intellectual and emotive play-centers; music comes from w/in us. Learning to speak a musical language, say beautiful things and tell captivating stories is not a skill that can be reduced, boxed up and sold. There are definitely many techniques for focussing and refining our musical speech, but in the end . . . a man must move foward from where he stands. In other words, you might get really good by practicing all the right techniques, playing all the right notes, and learning to not play a lot of right notes, but you won't ever be your own master w/o walking the road your own mind and body generate in front of you.
A great example is a local drummer here in Juneau (who shall remain nameless to protect the innocent). He is by far one of the best drummers I've ever worked with. He's tight and groovy, he listens incredibly and he WILL make you sound like a better musician because of just how well he can track your pocket. But the truth is, even his best friend will tell you, man, he is sooo great! I just wish that he'd open up a little; just be a little more raw occaisionally -- you can tell the potential energy is in him, but he just won't let it out!. So, IMHO, he's a great drummer but, for whatever reason, I don't really think he's his own master on the drums, and if you ain't your own master, you're no master.
So, to draw this rambling to a close, it's important to remember that, although there are a lot of great methods for becoming a better musician, you can't be your own musical master w/o knowing your own musical mind. Technique and methodology is a double edged sword; sometimes it shows you your road, and sometimes it hides it from you. The bass-player, like all musicians, has to walk his/her own road and find the zen of his/her own musical spirit.
For a great take on all this, I highly recommend Free-Play: Improvisation in Life and Art by Stephen Nachmanovitch (
http://www.amazon.com/exec/obidos/ASIN/0874776317/qid=1049308944/sr=2-1/ref=sr_2_1/103-6062608-9059006)
