There's nothing in the logs - apparently the process didn't even have a chance to truly start. Looked at Services and saw no one would be hogging the HTTP ports (except Jitterbit, which I already shut down). So what's going on? Dropped to cmd, and here's what httpd.exe said:
Well, someone is hogging the port after all. Time to whip out TCPView (can't believe I'm doing this) and... guess who? Skype! Apparently it sneaks in to enable firewall evasion for peer connections (details here) if possible. Disabled that and things started to work.