The American League Eastern Division has long been the toughest division in baseball. In the last 15 years, the AL pennant has been won by a team from the East Division 10 times. Now, that's 10 out of 14 pennants in 15 years (the playoffs were cancelled in 1994 due to a players' strike).
So it should come as little surprise that the top team from the AL East has handily defeated the top team in the AL Central, while the team with the best win-loss record in the major leagues has gone down to defeat at the hands of the Wildcard team (from the AL East). Because of the unbalanced schedule, of course, the LA Angels of Anaheim played a disproportionate number of their games in a weaker division which they dominated, while the Tampa Bay Rays and the Boston Red Sox each played the lion's share of their games in a much stronger division which they both likewise dominated.
The only surprise really -- and a pleasant one at that -- is that the division champion was, in fact, Tampa Bay.
Meanwhile, pressing the point further, the wildcard team was also from the AL East, and has also won it's preliminary series. As such, the upcoming series for the American Pennant will feature the Tampa Bay Rays and the Boston Red Sox.
Oh, and some stuff is going on in the National League too.