Here's just a quick note on the eve of the Eagles' second appearance in the Super Bowl. The following is every Philadelphia team to win a championship or appear in a championship game/series in the four major sports in chronological order:

Notes: NABBP=National Association of Base Ball Players, the precursor to the first professional league, the National Association.
ECL= Eastern Colored League
BAA=Basketball Association of America, the NBA's forefather
AFL-The 1926 American Football League was a one-year rival to the NFL. It had no affiliation to the 1960-69 AFL. The Quakers were shunned by the NFL champion Frankford Yellow Jackets but met the seventh-place New York Giants in an exhibition of sorts and were pasted, 31-0.
Frankford—Had two ties but the NFL just ignored ties back then, so they don't figure into Frankford's winning percentage.
Hilldale—Was known as Hilldale Daisies, Hilldale Giants, or just plain Hilldale depending on the source.

You'll notice that the Phils now have gone the longest of any Philly club to reach the finals. You'll also notice that the USFL Stars, not the 76ers as is widely reported, are the last Philly team to win a championship.

Philadelphia teams overall are 15-19 in championship series/games. That's a .441 winning percentage. In total championship games, they are 69-83 (.454).

Also consider that the Eagles have gone the third longest in the NFL without winning a championship (since 1960). The longest wait is since 1947 by the Cardinals, during which the franchise moved twice (from Chicago to St. Louis, then to Arizona). The second longest wait is owned by the Lions (1957).

A good sign is that only one Philly team with a better record lost in the championship round (1983 USFL Stars):

Then again, as a Philadelphia fan, I am of course grasping at straws. Why do you think I wore my Reggie White jersey today if not to pay tribute to the mighty football gods?