Ah, but when you sign the top free agent pitcher and top free agent hitter in the same year and play in the fair city of NY, don't kid yourself my friend, the expectation level for the Mets is just a shade below that of the Yankees...if they don't contend (And yes they're only 3 back, but they're also sub -.500 currently), they will be crucified by the NY media and fans.
As for the Sox, they have their 1 and 2 starters out, but are still in second place, 4 games behind the O's who are riding an 8 game win streak, a pace which won';t continue, the pitching isn't strong enough, though the hitting is the best in MLB. The Sox need to merely tread water till June and hopefully get back Wells and Schilling (and Wade Miller should be in the rotation this weekend) and they'll be fine.
The Yanks on the other hand should be concerned. They are an aging team and the pitching staff has been inconsistent at best (middle relief is awful), and a lineup of high priced, aging veterans (for the most part), who aren't putting up numbers comensurrate with their salaries. I think this may be the year that Steinbrenner's head explodes like a character in the movie "Scanners".