So here's the deal. When you rely on a multifx pedal for your tone you are going to want a very clean amp to run it into. Flat, pretty much. Usually you want to run straight into the power amp, actually, through the "fx return" jack.
So why not just get a power amp? Couple it with a PA speaker and you will have a great delivery system for your multifx pedal. The first two links are one example - about 300$ or so, for a clean 150w of speaker power, with more wattage on tap for extra clean headroom. Not a bad way to go, plenty of volume, although more speakers would probably be nice.
The third link is to a powered cabinet. Again, this is the way to go if you're amplifying a multifx pedal - clean, full-range amplification. The disadvantage of this method is that you're limited to the one speaker, you can't add on to it without more equipment (ie a separate mixer, another power amp, more speakers, whatever).
The two links after it are two of the cooler buys I've ever seen... all tube amp heads for less than 200$! The Epi Valve Jr and the Crate V Series V33H.... tubes tend to add a bit of warmth to digital sound, I think you will find that they would work well together! (and that Crate looks like a great deal... just might have to get one... dang... I've got the Epi Valve Jr, which is a great amp, but it's only 5 watts, which means it doesn't have as much clean headroom as I'd ideally like - which means you can turn up louder before it starts to break up, basically - 5 watts is still loud enough to jam with a full band, if you get good enough speakers though!).
If you do go with a guitar amp, then you'll need a cab with guitar speakers... this is important, as guitar amps put out a good deal of high frequency icky hiss (unlike the power amps mentioned above), and thus you need guitar speakers, which have less high end response to filter that out.
EDIT: I didn't actually ask what your price range was, but I figured I'd start by low-balling it. Anything I've mentioned is good enough to play with a full band, both tone and volume-wise! You surely don't need a 100w tube amp to get a rip-your-face-off tone, in fact 100w is usually too much amp to gig with, since you have to turn it up so loud before it really starts to get that sweet frickin cranked sound... (remember what I said about headroom earlier!)
EDIT: Watts work logarithmically. So 100w is only twice as loud as 10 watts! The big difference isn't in volume, it's in headroom... I usually consider 50-60 watts to be the most you ever need, especially if its a tube amp!
Saul