After SMC 1.8 Update, mid-2011 Air won't sleep, battery drains constantly

TL;DR: Installed SMC 1.8, computer won't sleep. Do I have to do a full system wipe / restore?

I've seen a few other threads noting issues after the SMC 1.8 update (like https://discussions.apple.com/thread/4773371 ) but nothing matches my exact symptoms so I'll post a new one.

For the past week, it seems that my mid-2011 13" 128GB MBA won't go to sleep, either by closing the lid or Apple->Sleep from the menu. The bottom of the case is perpetually warm and the battery drains from full to dead in ~6 hours. I had installed a couple of pieces of software around the time that I did the SMC 1.8 update so I'm not sure exactly what the culprit is but I'll go on a limb and say the SMC update is the likeliest suspect.

I have tried the following steps to no avail:

• shutting off Wifi and Bluetooth (and disabling "Wake on" features)
• rebooting
• powering down and resetting the SMC
• cursing in several languages

When I run "pmset -g assertions" this is the summary output:

2/14/13 2:28:35 PM EST

Assertion status system-wide:

PreventUserIdleDisplaySleep 0

PreventSystemSleep 0

PreventUserIdleSystemSleep 0

ExternalMedia 0

UserIsActive 0

ApplePushServiceTask 0

BackgroundTask 0

So as best I can understand the issue, there's no user-level software keeping my system running and thus I'm blaming SMC. I'm at a loss for next steps... I've never tried the genuis bar but I'm skeptical they can add much, so am I down to doing a system restore or is there something else to pursue first?

Tyler