Re: Distortion
Nice amp. I think the AVTs are sadly under-rated. Am I right in thinking the AVT has a single ECC83 (12AX7 for our friends across the pond) in the pre-amp?
cab suggestion: if you wanna go with an all marshall setup then the 1936 is a decent 2x12 cab. Depending on the application you're looking for though. Although a 4x12 won't neccessarily be louder it will appear louder and this isn't always a good thing. We've all been to see bands where one of the members is way louder than everyone else, not good. If it was me I'd go for the 2x12 1936. It's a good cab and I don't think price difference between them and the 4x12's is justified in the performance. You'll be glad when you get to a gig and realise you're playing upstairs!
Another pedal I'd recommend in the DS-1 price bracket is the Digitech Bad Monkey, can be bought for bare money now, though it is considerably more polite. Good for adding weight to your crunch tone rather than a stand alone tone running through your clean channel.
Anything by Boss is good. They don't make bad pedals, though they don't really make great ones either. However, you always know you're safe with them.
Danelectro are usually rubbish at pedals, though they came out with a good range in the Wasabi. Look into these because they're good and have a lot more versitility than most pedals at this price. Avoid all other danelectro ranges like the plague though. They are to tone what Macdonalds is to the British Heart Foundation, seriously.
That's about all I can think of right now, hope this helps.