I'd say the biggest challenge you'll face is finding a good death metal tone out of any smaller amp of quality. They're mostly are designed for more "refined" tastes than your typical metalhead
(no flames from vicious metalheads, please--I actually consider myself a "refined metalhead."
In other words, my music listening spectrum spans anywhere from Larry Carlton to Lamb of God).
Anyway, in the first category, i.e. those amps that have an overall metallic flavor but are built for the "small stage" (aka living room), Soldano's Astroverb 16 might do the metal thing rather well, as would a Bad Cat Hot Cat 15 (or 30, if you can swing it). The Hot Cats also have a reputation of sounding good at lower volumes.
You might also want to look at the Mesa/Booge Rectifier Preamp (or Rec Pre as they're known) through a decent power amp (the M/B 20/20 is certainly a good choice). They get somewhat mixed reviews but I think a lot of people want to compare them directly with a Recto head and/or don't read the manual closely. Manuals are practically required reading for all M/B products to get the best out of 'em.
In the "tube-ish" category that can do metal, I also agree that the Vox Valvetronix amps are a good compromise between modelling and tube technology. The output curve is modeled with an analog tube circuit rather than digitally, which is a rather ingenious design and sounds good, too. Look for one with the power-scaling feature (down to the 30W version, I think. It's not the same as London Power's more "organic" design, but a reasonable facsimile). Tech 21 Trademark amps also have a reputation for being very warm and dynamic--again, not a tube-based solution but very well-respected by a lot of tube devotees when tubes are not a viable option.
In the middle ground, roots to rock but not quite metal, I would strongly recommend checking out a Cornford Carrera, Harlequin, or Hurricane (depending on your budget and power requirements). All three are
monster amps that can really rock and are as well-made as anything out there. If you have a BIG budget, the Hellcat 30 combo would be hard to beat.
Mojave also makes some really nice stuff--either the Coyote or Sidewinder would be a good choice for your needs--and Reeves has an amp that is very similar to the upcoming Suhr Badger: a Custom 18 (they offer other wattages as well). Personally, I'd choose the Badger if they were both available because I am a big fan of John and his designs, but the Custom series uses the same patented power scaling by London Power that the Badger uses, so I would expect similar performance.
In the third category (roots to rock only), the Mini-Z is a
great little amp--very warm and open sounding--and the same would go for the Bad Cat Mini Cat II. Both of the Swart amps are simply
incredible tone-machines. The Carr Mercury that was mentioned is a phenomenal amp, but also doesn't rock in the metal zone, IMHO. Finally, don't forget the THD UniValve and BiValve with built-in HotPlate attenuators. The BiValve is more suited to hard rock if you have a choice.
If cost was not a major concern (and playing metal was), I would probably go with a Hellcat or possibly the Hot Cat 15 or 30. If cost was the primary factor, I would say either the Valvetronix or the Trademark amps are really good for the price--one more of a "modern" flavor (Vox) and one more "classic" (Tech 21).
I apologize to everyone for rambling on so much. I tend to get carried away when talking about such things!
If you've made it this far, thanks for hanging in there with me and if you haven't, well then,
!
And no matter what, keep rockin'!
