Boy, I plowed through this thing. My first, incorrect entry "ImeaniT" for 1A: "No, really" (IINSIST) at least gave me ISLE and TROI, and from there I was off and running.
I like this themeless quite a bit. The double-I start is very nice, it's very Scrabble-y, as they say, with those Js and Zs, and has lots of good fill. SASHAY (4D: Walk alluringly) is fun, TROMBONE (37D: Ska band instrument) is something you don't often see in a grid, LAZYBONES (35D: Do-nothing) is great. Earlier this week there was a little conversation on this blog (and others) about whether or not "adorbs" should be acceptable fill. I say yes, and I also say a big yes to LOLZ (32D: Online hilarity).
We've got some fun pairs in ZANY and SANE, and NERUDA and Poe's TOHELEN, and 14D: Go astray (ERR) and 25D: Not stray (BETRUE). We've also got some fun clueing in 47A: Scare quote? (BOO), 16A: High-minded sort? (AVIATOR), 27D: Debugging tool? (ZAPPER), and the sure-to-be-controversial 19A: [Can you believe they wrote this?!] (EMPHASISMINE). Me, I like it.
In fact, I like the whole thing, as I believe I said earlier. Just a little LST here, and a slightly odd SQUATJUMP running down the middle, but that's not much to pay for the rest of this. Very nice.