i did holland america to alaska a few years ago but would'nt reccommend it (terrible service). did a celebrity cruise in september on one of the ships they do the alaska's on (shorty cruise they do in the pacific northwest a couple of times before they reposition the ships back east)-and was realy impressed with them. very nice rooms, great service-good food. and allot of little 'perks' the other lines don't do (check out their 'concierge class' rooms-not much more than a standard, but the perks and individual attention is awsome).
i booked directly thru the celebrity site and did the whole 9 yards. they did my airfare, shuttle to and from the dock and my cruising. i probably could have saved some going through a travel agent-but this way all the stuff was sent directly to me, and any updates/changes were instantly emailed to me (vs. having to be relayed by a t.a.).