Music Devinoch has been known to enter/exit a room to:
"Baba O'Reilly" by The Who (Best. Entrance. Music. Ever.)
"Aerodynamic" or "Digital Love" by Daft Punk (depending on the mood)
"69 Police" by David Holmes (exit only - somewhat cribbed from "Ocean's 11")
"...Slowdance On The Inside" by Taking Back Sunday (exit only)
"English Summer Rain" by Placebo
"Midnight In A Perfect World" by DJ Shadow
"Ashes" by Embrace (entrance only)
"Promise (reprise)" by Akira Yamaoka (exit only)
"Fool's Gold" by The Stone Roses (for long exits/entrances only)
"Waiting Room" by Fugazi
"Teen Angst" by M83
"Escape Artists Never Die" by Funeral For A Friend
"If They Move, Kill'em" by Primal Scream (remixed by My Bloody Valentine)
"Journey To Reedham (7 A.M. Mix)" by Squarepusher (more in-transit music, really)
"Circles" by Soul Coughing (also more in-transit, but can serve as entrance/exit)
"John The Baptist" by The Afghan Whigs
"Million Miles" by J. Ralph (exit only)
"All Tomorrow's Parties" by The Velvet Underground
"Everywhere You Turn" by Longwave
"Take The Long Road And Walk It" by The Music
"Be There" by U.N.K.L.E. (w/ Ian Brown)
"The Staunton Lick" by Lemon Jelly (exit music - but I admit to cribbing this one from the british TV show "Spaced")
"I Woke Up In A Car" by Something Corporate (entrance only)
"Looking At The World From The Bottom Of A Well" by Mike Doughty
"Born Of Frustration" by James (entrance only)
"Hyperballad" by The Twilight Singers (exit only)
"Donna Everywhere" by Too Much Joy (entrance only)
"Mr. Brightside" by The Killers
"Get Higher" by Black Grape (exit only)
"Hoover Dam" by Sugar (entrance only)
"Anybody Wanna Take Me Home" by Ryan Adams (exit only)
"Enjoy The Silence" by Failure
"At Nature's Mercy" by Hot Rod Circuit (entrance only)
"Southbound Pachyderm" by Primus
"Just Like You Imagined" by Nine Inch Nails
"Soon" by My Bloody Valentine (exit only)
"Above" by Blue Man Group (entrance only)
"Christmas Song" by Mogwai (bittersweet exit music)
"Nightdrive" by Jimmy Eat World (exit music only - I would have also said "My Sundown" but that would have been cribbed from the "Global Frequency" pilot that never aired...)
"Long Live The Party" by Andrew W.K. (entrance only)
"Never Gonna Come Back Down" by BT (entrance only)
"Not The Same" by Ben Folds (exit only)
"When I'm Dead And Gone" by Fury In The Slaughterhouse (entrance only)
"The Remote Part/Scottish Fiction" by Idlewild (exit music only)

You can see I've given this quite a bit of thought...