The best oil for a manual transmission?

[J.DeFeo]

I have a 1992 535i with a 5-speed Getrag manual transmission. What is the best lubricant to put in it? I'm not having any problems, but I just bought the car and want to flush and replace all of the fluids because I'm extremely anal.

I've heard marvelous things about GM Synchromesh (and the exact same thing in a cheaper bottle, Pennzoil Synchromesh). What about Redline, specifically which kind? How about just plain old ATF?

Thanks in advance.

[Ausmpower]

What colour label is stuck on the box?

It identifies which oil (atf or gear oil) the box was designed for.