So I've been in quite a bit of debate about what to get. I've got a Line 6 POD X3 Live so I'm all set on FX and such. There is a left and right output which I want to make use of and I'm not sure if I should get a combo/stack tube amp and use 4CM or buy a pair of active PA speakers. The advantage I find with the PA speakers is that it's a lot cheaper and I have stereo sound (great for dual-tone). The advantage of a tube is that it has a really nice and strong sound.

What would you guys think is the better alternative? My budget is around $600-800. Oh, and I just like to play loud and metal if you were wondering. Thanks!
Well if you go with the PA speakers, what power amp are you going to use?

I'd reccomend a decent guitar amplifier over using a PA any day of the week, regardless of making any use of the stereo functions or not. Guitar amplifiers, guitar speakers; they're all constructed specifically to perform best with guitar equiptment. A PA is designed to amplify as cleanly as possible; I think you'll probably find your tone to be quite lifeless, quite 'un-soul-ful'. You'll probably find that a lot of stereo effects aren't all they cracked up to be anyway. If you're interested in stereo however, I'd reccomend a decent head, and then perhaps a couple of 2x12 cabinets.
Thanks for the reply! That does make a lot of sense. I guess I was mainly considering to use the amp and cab models to do all the work. Right now, all I've got going is a pair of computer speakers running through the headphone jack so I'm really open to anything.