I like the classic SVT+Sansamp tone, but imho it's just way to expensive, Orange Bass Terror is awesome,
TecAmp has great amps, too. For bass, I wouldn't go full tube, they're most of the time very pricey and
heavy as fuck (weight) but there are really cool amps that are solid state or have digital poweramps and
a tube preamp that sound really, really good, are very lightweight and sometimes really cheap, like the Orange.
If you have the chance to try some bassamps, try everyone of them!
http://www.thomann.de/gb/ebs_cl_450.htm
-cool rock sounds, like the name says, classic, but the SVT is classic, too
http://www.thomann.de/gb/tc_electronic_rh_750.htm
-really great digital amp, loud as hell, multiband compressor, loads of distortion if you want
http://www.thomann.de/gb/mesa_boogie_m9_carbine_head.htm
-my favorite mesa bass amp, in my opinion better than the SVT but still overpriced
http://www.thomann.de/gb/markbass_little_mark_rocker_500.htm
-pretty cool small amp, sounds pretty nice and is very light
http://www.thomann.de/gb/hartke_lh_1000.htm
-pretty cheap amp with just a few options but a good sound
http://www.thomann.de/gb/kustom_de300_hd_head.htm
-really cheap amp, but it sounded really, especially for the price
don't forget that many people are using pedals for the bass sound, like the sansamp or stuff that wasn't
created for bass, like the metalzone or tubescreamers, it really depends on the bass, the strings, the
player and so on. In my opinion way more than at guitar.
The bassplayer in my old death metal band was a hell of a player, he used a cheapass Ibanez with an old
Vox guitar amp in the beginning and still had a decent sound, I think you get how awesome he sounded
when he switched to a nice Warwick, better strings and a SWR amp
At the same time, I met a band, rich bassplayer who sucked ass, he had a 2500$ Spector, an Ampeg SVT-Pro
Ampeg 8x10 cabinet, Sansamp, a second amp that was setup clean into a 1x18 cabinet and his sound sucked.
If you're after a modern metal sound, played with pick, distorted (at least a bit) I would go for an amp that has
a nice, clean sound that can be shaped a lot and use a pedal with it, that way you can get a few different
sounds and it's even cheaper.
Oh, and don't forget the cab!!!
I would go for a 4x10 or 2x12, 8x10 are just to big imho and 1x15 aren't that tight most of the time.