Personally I would rather forget about the third movie. That movie had the worst possible ending for the series.
I think I'm with you on that one. I think it would be possible to use the show as somewhat of a timeline correcting device to lead into the next film and from the couple articles I read, Fox giving the show another season, might be it's goal.
On the other hand, the new film could completely ignore what's going on with the TV series and just move forward, building on what's been shown in the films. After all, it's not like the show "Smallville" had much of an impact on what was done to re-launch the big screen Superman franchise.