I'm gonna put another vote in for the Laney LC-15, although it's worth noting that they've since abandonned the HH invader, the version I got came stock with a 10" Celestion speaker. It sounds good, but for under £200 is the best tone you're likely to get in that price range, hands down. And because it's got a master volume etc, you can get useable tones at social volume levels.
I've heard really good things about both Line 6 and Vox's Valvetronix amps as far as modelling amps are concerned. And my friend swears by his Tech 21 10 watt amp. If I went back, I'd deffnitely have looked into one of those, even though it's solid state.
As for the MG15 reccomendation, I can't say I thought much of any of the ones I plugged into. It always seemd kind of flat and restrained and a bit grainy, and it was relatively unresponsive. There's worse out there, but I think the main selling point for the MG series is that it says Marshall on the front and doesn't break the 100 pound barrier which makes it a very realistic option for people without their own income, like students.
