I have a proposal for another form of game which could be used in friendly games as well as for tournament games: instead of fixing the timeout as a certain number of days per move, fix a total timeout per game. this copies the usual system used for real-time games in chess, but if a sufficiently large time is chosen, is as good as correspondance games.

for example, a one-day game must finish within 24 hours. the first player to overstep the limit loses on time. this is as good as a realtime game.

a 60 days game is probably more than enough for an ordinary chess game. in a lot of positions you can answer fairly quickly, in others you like to take your time. it's up to the player then to manage the allowed time. you want to take a week to think about the first move? fine, but the rest of the game still has to fit into the allowed time.

some care must be taken to allow for time zones.

I think this form is particularly well adapted for tournaments. take, for example, the coming gothic tournaments. the proposed timeout is 7 days. it is dead certain that with the number of players which are going to participate in this, there'll be the professional snails who like to take their time up to deadline-1 minute. as I remember, Ed showed us recently a game of his that lasted
80 moves; such a game would take 560 days, more than a year and a half...

you might get games that when a player is loosing that he waits untill the last possible minute to move his piece , unless the other player was online at the exact time he would loose the game

What about to add a rule that each player must make a move within, say, 10 minutes after his opponent's last move?

no. if you have a 1 day game, you have an allocated 12 hours; the opponent too. if you wait until your last minute, you have one minute, the other guy 12 hours.