This is probably the oddest build I've made, but it's actually surprisingly extremely powerful:
Personal offensive power, range, armor, block, healing, buffing, debuffing, hordes of summons, this guy's got it all. By the end, I was flooding almost the entire floor with my summons, taking almost no damage (thanks to Barbarism), instantly healing what little damage I did take, freezing every enemy who came anywhere within four squares of me, blasting everything across the floor with Astral/Ice/Fire damage every time I stood still or attacked. No idea how well it would work on earlier cycles (in particular the first one), but this got me through cycle eleven no problem.