For me, it comes down to what I'm going to be using the bass for, how often and then what I can afford or justify spending. I love vintage Japanese Fender's so anything from the 1980's and pre 1990's. The only mod I have to do is upgrade the pickups but these are good enough for pub gigs, club gigs and all the way up to big venues including stadiums and can be had for under £1k.
I'd also happily spend a little more and buy an American Vintage Fender which will again, do all of the above, be a little more unique but come in at around the £2k range. I wouldn't however buy a standard American Fender as they are no better than the vintage Japanese Fender's and for me in a lot of cases, poorer yet more expensive.
If I was pro or doing a lot of paid work then my budget would probably be between £2k - £2.5k and I would settle on an Fender American Vintage. I do have a bass on my list to buy, a late 1970's fretless Fender Precision. My budget is around £2k, anything over that and I feel it's a waste.