Yeah, nooby question.

I got a Fender Jazz recently and right now I'm running it through this awful little amp called a Watson or something. Which amps would you recommend that go especially well with a J-Bass? It's really just nice crisp sound I'm looking for, no fancy 20-dial monsters, in about the £100-£200 range. Ideas?
Seeing as your In the Uk, (i assume seeing as you said the price in sterling) check out laney. if you dont mind going up to £200, you can get the RB4, or RB5, depending if you want a better EQ or louder, depends if you play in a band or want to i suppose. But yeah, Laney
Ampeg.....ummm fender rumble 100w 2x10, i dnt know the exchange rate as of 3-12-09 for British2U.S but, do u want a combo amp or a stack??? What type of space are you going 2 be filling w/your amp...room, house, club/pub,????
<Insert Witty Comment Here>

1981 Fender Lead I Seymour Duncan humbucker, Mesa BoogieIIIRectifer, MKIIRhodes,PRS
Look at Acoustic...someone will say it eventually. I don't have a lot of experience with them, but I'm sure some one can tell you what they sound like better.

Mostly, go to a store with a lot of amps and play your bass through them.
I have:
Acoustic B200H+B115 cab, Schecter Stiletto Custom 4, Rondo Fretless, Boss EQ-7.

Some men just want to watch the world burn. And they work at Behringer.
Well since you live in the UK, try and find a used trace elliot. They are awesome, great tone, Very well put together.

Ibanez GSR205FM

Trace Elliot GP7SM 200watt bass combo
Not to give a 'stock' answer, but get down to your nearest music shop and try as many as possible. We can make suggestions all day to help guide you to the better ones, but you know better then anyone what tone you have in your head as the one you like. Read reviews, get suggestions, and take them as just that: suggestions. At the end of the day you're the one sitting in front of it for hours on end, so you should try as many as possible, that way you can make an informed decision when it comes time to lay your cabbage down on it.

Personally, IMHO you can't go wrong with Hartke amps.
-Guitar Gear-
1995 American Fender Strat, EMG 85 pup
Randall RH200 Head
Marshall 1960a Cab
Woods Acoustic
-Bass Gear-
Spector Legend 4 bass
Washburn Bantam bass
Hartke HA2500
Fender Bassman 410H
Play what you love, love what you play
Thanks guys. I think I'll head down to my local music shop and have a blast through some of the amps they have, see what's to be heard.