The spider II's are supposed to be some pretty good amps, but I don't have any personal experience with them. A few questions though...

How much are you willing to spend on an amp?
How big of an amp do you want, 1x12, 2x12, head & cab?
Do you want a tube amp or solid state amp?
Do you only want to use the amps distortion/overdrive, or do you want to use a distortion pedal infront of the amp?

A couple tube amps that come to mind would be...

Peavey Classic 30 which is a 30 watt 1x12 tube amp. This would probably need an overdrive pedal infront of it to get good metal tones, but it's possible on it's own.

Peavey Triple XXX 1x12 tube combo. I have the head, and with some new preamp tubes, this baby can pull off a wide variety of tones

Traynor YCV40 1x12 tube combo. These are supposed to be excelent for the price.

Carvin Vintage 16 or 112 Nomad. No experience with these, but the hear say if pretty good

Those are all that come to mind right now, but if you answere the above questions, we might can narrow it down a bit.