There should be a way, or even a mod/plugin/(whatever phpBB calls them) that does it. If not, shouldn't be too difficult to program anyway. Sticky-site has a list of all topics you posted on with new replies, which I think is more useful for some cases.
The issue is finding said plugin and being willing to risk another spiel of the forum going to hell for a few days just for that feature, or alternatively trusting me or another member to not fuck the database up with their code for option 2

I'd definitely put it in the list of things to add during the next archiving, since this (in some variations) seems to be the most requested feature. Then again, if you nag too much someone might wanna spite you :3