Realistically, both ASU and Arizona could make it in. Arizona has been struggling over the past 10-12 games but they still have 18 wins and the hardest schedule in the country (RPI - #1). ASU has a softer schedule (RPI - #74) but are still in good position.
I think if Arizona can win a couple games in the Pac-10 tourney (first round against OSU) they'll make it in. ASU needs to beat USC in the first round which is a big challenge.
But, cheers to the Pac-10 this year. A very realistic chance to have 7 teams go to the tournament (UCLA, USC, Stanford, Arizona, ASU, Washington St. and Oregon).