ASHBURN, Va. _ Mike Shanahan's once-unquestioned legacy was
fading rapidly.   Seven weeks ago, Shanahan was 14-27 after
roughly 2½ seasons in Washington. To fans with short memories,
he had become associated as much with Donovan McNabb failures as
with John Elway successes. Though often touted as a Hall of Fame
coach by his peers, it had been seven years since he coached a
playoff team.  Turns out, he still knows what he's doing.  "You
understand as a coach: unless you get it done, people forget
very quickly what you've done," Shanahan said Monday. "So that's
why I think a game like winning the NFC East, you get a game
like that, you want to find a way to win it. Because once you
do, that momentum starts again. ...  "Unless you take advantage
of that opportunity, people forget very quickly."  The Redskins
(10-6), division winners after a 28-18 victory over the Dallas
Cowboys in the season finale, will host the Seattle Seahawks on
Sunday in the franchise's first playoff appearance since the
2007 season. It's t