Very tough decision.
I've only actually heard Driving Rain, Chaos and Creation, and Memory Almost Full. It almost depends which mood I'm in. I think Driving Rain is easily one of his most underrated albums. I like all the songs, I used to listen to that album over and over when it came out.
When I first heard snippets of the songs from Memory Almost Full, I was underwhelmed, and didn't expect much out of the album. But of course I still bought it. And I was pleasantly surprised. Also, I must say that this album really grows on you.
But I ended up voting for Chaos and Creation in the Backyard. This would easily by critics be considered his best album so far this decade, and I can see why. Plus it is quite impressive that the guy played all the instruments on it. It really is a pleasant listen.
But it looks like I need to check out Electric Arguments!
Oh, and I am a fan of classical music. How is Ecce Cor Meum?