[MHarris]

I've never played .5/1 and only played about 5k hands of 1/2 before moving up, but here goes.
VP$IP- I generally try to keep mine below 20%, but at the microlimits the passive play may allow you to play more hands. At 1/2 i was a little over 22%, 2/4 it dropped to 19%, and at 3/6 it is about 16%. I can attribute the drop at 2/4 to more aggressive PF play by my opponents, and the drop at 3/6 to more aggressive play and the 1/3 blind structure.
PFR%- Mine has always been about 8% at each limit. Some successful players are a little higher, some a little lower. 7-10% is solid here.
W$WSF- Upper 20's seems good here. Anything above, you are playing too tight PF, anything below, you should tighten up accordingly.
W$SD- I think most of the better players here agree that 52-55% is a good range to be in.
Postflop Aggression Factors- I think this stat is most telling in your success if your preflop game is good. Without preflop stats included, your total aggression factor should be at least 2, with aggression factors on each individual street reasonably close. If your AF is below 2, I can assure you that you're missing bets.
BB/100- 2 is pretty good, 3 is something to strive for. My decisions on when to move up are based on maintaining 3BB/100 or as close to it as possible over a good amount of hands.
VP$IP from SB- This varies from limit to limit. At .5/1 or 1/2 up to 35% seems reasonable. As you move up in limits, that number gets smaller due to more aggressive play and blind structure changes.

Also, Bison's post "Some notes on notes" has a great rating system for your opponents. I'd recommend using it, along with the auto-rate feature on the new version of PT. If you don't have it, I'd recommend downloading the patch and help files....it practically eliminates all the work involved in rating your opponents.