This isn't aimed at anyone in particular, but this thread cracks me up. So much of the instrument that we play is personal opinion and prefeence - I just don't get how one bassist can tell another bassist that his/her choice of their particular instrument, number of strings, etc. is "wrong." I prefer to leave the prejudice against bass types up to the guitar players; next thing you know, we'll be saying that you can't use electric bass for jazz
I played 6 string basses almost exclusively for about 13 years, through many, many different types of gigs. It wasn't for a "cool" factor, it was really because I was more comfortable with a 6 string at the time, and I liked the sonic possibilities that it opened up. Several years ago, though, I dislocated the index finger on my left hand at the middle joint, and despite proper medical treatment and physical therapy, it's never been the same and I find that my finger tends to tire and hurt after extended playing time, so necessity more or less forced me to go back to 4 string, adding 5 strings to my aresenal (before my injury I hated 5 strings, I still prefer 4's and 6's over them), and using 6 strings more sparingly, which has helped with the issues. Before my finger injury, I never experienced any hand-comfort issues
Over the past 2 years or so though my finger has gotten significantly better, so I have been able to use 6 strings more. What I find now though is that I pick basses on a more gig-specific basis - some gigs lend themselves more to 6 strings, some more to 5's, some to 4's. If I am going to solo, I like the extra range that the 6 affords, but if I know that I am going to be holding down the bottom end for hours at a time, I am more comfortable with a 4 (finger-wise).
The whole silver lining for me is that the injury more or less "forced" me to explore different basses. From that I can truly say that each bass-type has it's place, whether it's due to the gig type, song type, player preference, coolness factor, or whatever. For me, each bass brings something different to the table, and different basses can influence my playing in different ways. Just because I don't like 14 string basses doesn't mean that they don't have a valid place in our art, the same goes for someone who wants to play roots on the E string on a 1 string bass.
My move back to 4 strings was done out of necessity, and although my finger injury sucks, at the very least I got a different viewpoint out of it, and I believe that my playing has improved as a result. YMMV.