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Youre not giving us enough clues.

Genres?
Scale length?
Style, Jazz, P, MM?
Active?
Passive?

Lots of other things.

 

Also...price range? And what is lightweight to you? Under 10 lbs? 9? 8?

 

Genre isn't really critical since you can really use any bass for any kind of music. But the price range helps. If you buy used, you can get a much better bass for the price than if you buy new. Otherwise your requirements are pretty broad. I would suggest trying out a bunch of basses if you can. See what fits you. People will come on and suggest "their" favorite basses, but that doesn't mean you'd like them. I could suggest getting a used Spector Legend, since I really like them and they fit your criteria. But whether you'd like it or not, you wouldn't know until you actually played it.

 

There's Spector Legends going pretty cheap on Amazon.com right now. Go to Electronics>>Musical instruments>>Instruments Outlet. You have to add them to your cart to see the price.

http://www.amazon.com/exec/obidos/t...t_shr?_encoding=UTF8&m=ATVPDKIKX0DER&v=glance
$257.98 for a Spector Legend 4, clear

http://www.amazon.com/Spector-Legen...8&s=musical-instruments&qid=1249352934&sr=1-2
$257.98 for a Spector Legend 4, black cherry

Lots of other good basses on there, just poke around.