tdo-mf, post draft schedules, image scheduler. Specific enough for you? :)
every single scheduling function of wordpress was fubar'd after the upgrade, I'm sure you've seen the dozens of posts and requests for help. I eventually had to open every scheduled post and save it again for it to show up when it was scheduled to.
The easiest way to tell what's going on is to see what's changed in the db schema, as several of schedule related plugins have more to do with straight mysql entries then going through wordpress. I've checked the 2.7 changelog, but there's no mention as to any changes to anything time related. I've done a comparison of 2.6 to 2.7's tables and I can't see anything that's obviously different. It took about a week for the loggging in/out nonce issue to show up in the changlelog, so maybe this is something that still hasn't been put into the codex?
So back to my specific question : anyone know what's changed with the time db from 2.6 to 2.7? Is wordpress handling the time functions differently now?