Who to Start Message Board
You have to go week by week and look right before the deadline at who your opponent is starting and how many innings pitch you expect them to have. If they are gonna rack up a lot of innings (and/or k's) and you don't think you can match them, then punt the cumulative stats and go for saves and good matchups which favor you on the average stats. If you think you can match them on the cumulative, then try to do that and bench one or two of your closers.
This is assuming your league has a fair balance between average stats (favoring low IP squads) and cumulative stats (which favor the high IP squads, obviously). Every league should be set up in this way, IMO.
There's no right answer. The best thing to do is to have options both ways so you can play the matchups.