I think the Angels or Orioles will be amongst the biggest W-L column differentials, but also must look at playoff-fringe Phillies and Astros as potential party-crashers this summer.
Both Phils & Stros rounded out their 1-2 punch staffs to four and five man rotations, and the Phils now have a pen to hold up those early leads, both just need some better quality AB's from existing players at plate(mainly a return to form by Burrell and Hidalgo is needed for both teams), also both have nice AAA talent ready to shine on the mound and at the plate.
The RedSox, Marlins, Cubs, Oakland, and now Astros(4 Aces!) all have the combination that has been the best post-season formula of the past four years(IF NOT EVER), and that being a dominating set of Aces, yet Oakland has lacked the the Offensive punch(bombless since Giambi departure).
Too bad SF and Toronto have such anchors in an dominant Ace and MVP franchise batters in the OF, yet little more than journeymen surrounding them..bust!
Of the other contenders(NYY, KC, CWS, ATL, SEA, Minny, NYM, AZ, St.L), I expect only 2 or 3 of them to make the playoffs at best.