We've been starting at 12 playing 40 overs - finished at 5.30pm last Saturday, lovely. Time for a drink and a yarn, home before 7 (though as far as the Mrs is concerned, we finished about 6pm....). Our usual Kent League games are 50 overs, meaning we don't finish until gone 7. I think for anything below the top 3 leagues and the 2nd XI, 40 overs might be the way to go - it's enough time for people to bat, and 8 overs per bowler is fine. At the age of 41, I'm quite glad not to be standing out on the field for over 3 hrs.
With regards to teas, for league games I'd be quite happy bringing my own food (did miss having a brew at half time though) - if I were playing friendlies, teas is the best part of the day!