I recently upgraded from the 80+ to the AC15 and am very happy thus far. I need to get some effects pedals, mainly chorus, delay and comp. What, if any, multi effects pedals sound good in front of this amp? I may wind up buying three individual pedals, but would like to know a possible good option for more effects for about the same price.

it always depends on what you wanna do, if you already have an idea on what kind tone you're after, I'm pretty happy with the boss CE5, but I'm warning you, the AC15 has no FX loop, so if you're driving the amp even just for a classic crunch all time based FX like a delay will sound terrible in front, the AC15 is brutally loud but kinda lacks of clean headroom, I suggest it if you plan to do classic rock or hard without using dela FX unless you plan to use 2 AC15s, as for compression IMHO you won't need one, the AC15 already has a sweet natural compression if you drive it the way it's meant to be

I recently purchased the AC15HWX and dig it to the max. I have an AC30C2 and also an AC30C1. I have a few pedal boards and probably 20 or so pedals....maybe more. All these amps have there strong points, but as far as pedals that work with me:
Marshall Blues Breaker II -- Killer Marshallesque sounds, dialing it down smooth overdrive
OCD -- can't go wrong with this, however watch the tone settings, 10'clock is what I use otherwise to trebly.

Lastly, I saw a pic of an AC on an amp stand. Take that sucker off!!! It kills your bass and lower mids. Trust me on this. Or better yet, try it on the ground and then on the stand and ask someone to tell you their opinion. Wayyyyyyy to much highs and you lose all your bottom end. To me, if you want good tone, don't elevate the combo amps more than 12 or so inches. All of above is totally subjective of course......... : )