Dymero - 10:17 pm on Sep 17, 2012 (gmt 0)
If we take Google's call for good user experience as complete gospel, I don't know how putting "solved" on solved questions would meet this better. By everything Google has said, it should reward you for this. But, of course, not everything they say happens.
Still, I'd put the word in the title for solved questions. I know I prefer it, and I'm sure your users probably do, too.