if you play a wide variety of music get the Vox. You might have some use with the amp effects. The only bad side is that the vox has korg effects. I dont know if they are better than the korg multi effects pedals (which suck) but i have yet to play one.
The line 6 would probably sound the best out of your choices. Get a 2x12 if possible and it will give a fatter sound.
DO NOT get the AVT50. I have mine on ebay right now looking to get anything over $200. It will sound nice by itself and at low volumes but drums will easily drown it out. It also has none of the marshall crunch or tube tone. The clean channel is great but the distortion is definitely not something you would want to gig with. I replaced it with my first real tube amp and its a huge differance.