They all sound different enough and offer different enough advantages/features. I record and record for others, plus I do a wide variety of music, so no one bass (or even two) really does (best) everything I would like it to.
But an itemization and thoughts about each, in no particular order or preference as of 5/29/10:
1.) Fender Fretless Jazz Bass. My first bass, and still my only fretless after 15 years.
2.) Squier Classic Vibe Jazz Bass. Bought in '09, was my first, and only fretted Jazz Bass. Always wanted a fretted Jazz bass for that fretted Jazz bass slap sound, and it only took 15 years.
3.) OLP Stingray. Wanted something with that kind of Stingray sound, and at the used price of $99 in perfect condition, was a find. Bought it to use as a travel bass. Ends up being a killer-sounding and playing bass which I don't want to travel with now, but will anyway.
4.) Harmony Precision Bass copy. Bought it used 15 years ago for $40 from a friend, and still have not played ANY Precision bass or copy of one which I liked better in sound or playability at any price.
5.) 1981 Ibanez Musician bass. Bought it used to take the frets out of it to make fretless bass #2 for a Sting/Police tribute band, and couldn't bring myself to mod the bass. Turns out makes a killer slap bass, and is in great cond. Will never find another as nice for the money I paid. Quite unlike a Fender or MM slap sound.
6.) Fender Precision Sting Signature bass. the single coil defintely sounds different from the more common split-coil, and was meant for the stilborn Sting/Police tribute band. Great, rootsy, warm sound.
7.) Fender Aerodyne Precision Bass Special. I needed another Precision or Fender style bass like I needed a hole in the head, but never had seen this model but in pics, so I grabbed it (used). Plus I like the matching headstock. The P/J option is really cool to have in one bass. Perhaps my most impulse-driven purchase. It would be the first to go, probably.
8.) Music Man Stingray "Ray35". After selling my fretted six string basses due to continuing intonation woes beyond the 12th fret, needed something with a good low B that wasn't stupid expensive, and wasn't a 35 inch scale string length.
9.) Upright bass. It's an upright bass. Just ownership of one alone potentially opens up avenues you would never get as an electric-only player. I get called to record upright as much as electric dates.
10.) Carvin Fretless Six String bass. After giving up finding a fretted six string which I could afford which also satisfactorily intonated beyond the 12th fret, I decided to put this used bass on layaway at a store. I am really looking forward to taking this one home and reaquainting myself with the nuances of the six string bass as an owner.
I think the main thing is that all these basses sound different, and more importantly, different enough. Sometimes night and day different. Some I can't find again at the price/condition. Some I couldn't sell for remotely what they're worth to me. I can get by with less, and may thin the herd, but I loose something by doing so.
I draw the line at having a second of something just because I like different colors, or can't decide if I wanted a Seafoam Green Precision Bass, or Sonic Blue Precision Bass, for instance.
I treat them like collector instruments because I take care of the things I own and haven't forgotten all the hard-earned dollars it took to aquire them. But I also know I wouldn't buy something to just sit on display solely as an object of art or historical artifact to be preserved. I don't have that kind of money laying around. Everything is played.
