I live dangerously close to chicago, are you sure you want to make that offer? 
I absolutely love them and got hooked when I jumped onto the Godspeed/Do Make Say Think/Fly Pan Am train years ago. Still listen almost religiously to DMST but my Mt. Zion cd has been neglected.
I'm quite the other way round, barely listened to Winter Hymn.. when it came out but I'm a massive massive fan of ASMtZ. Caught them last year in Manchester (I'm from England btw! Hello) and got Efrim to write something on my copy of "This is our Punk Rock" vinyl, I realise this is very much the move of a fanboy but i couldn't resist.
But yeah Horses In The Sky is probably my favourite, they get better with every album. By the time it got to 'Hang on to each other' I was in love, such an amazing song that was captured at a campfire.
Don't think I'll be taking you up on the offer of Chicago though, bit far for me to travel.