I think in the near future we will see the move to 3/4" tubing. This is what I am using and have been pleased with the results so far. If anything the fittings can sometimes be easier to find. As for 3/8ths, fo-get-about it. Even 1/2" is pushing twoard the low performance end. These days you gotta go big. Wait around to long and Dell will release a watercooled PC with 1/2" tubing.
