Holliday without question.
Beltran is OK, but his power is on a bit of a slide, and his speed should start going soon. 2005 is recent enough for me to remember.
Holliday owns elite power, and if he can lift a few more flyballs it could be HR Armageddon for the AL West.
Also what Dan said is exactly right, beyond Lackey, Ervin and Felix the AL West pitching looks real tasty.