For summer tires, I always put the best tread in front because it wears the tires more evenly and traction doesn't really matter as much given your driving on pavement dry or wet. I your still within the the tread wear marks and don't try driving 70 mph in the rain, you should never have a problems regardless of where the tires are.
For winter tires, I never put only two new tires on. Your only asking for trouble regardless of where you install the them. That said, I also put the best tread up front so they wear evenly as well.
Hatch Nation #13 : Rally Revolution #13 : ROTM Jan '13
It's Bryan, not Brian
RSVT-170 Build in Progress
Derusting Rusty Build in Progress