Interestingly, it doesn't seem like all blades are created equal.
The sharpest seem to be "Feather" or "Sharks" from what I can tell.  I ordered some of both.  The Feathers aren't here yet, but the Sharks are very sharp.  Maybe too sharp for me.  I'm still trying to figure it out.
I started with Dorco blades, which are less aggressive, and I tend to like them.  So much that I bought one hundred (for $6).
You can buy blade sample packs and try different ones.  Everyone likes something different, I guess.
I started with two passes, but sometimes do three if everything is working and I don't seem to be getting any irritation.