Two ways you can go, Joseph. One is the more traditional waterproof-breathable route. That would be something such as the REI Shuksan ($299), a really nice rain jacket that uses eVent fabric, which I think is one of the really good waterproof-breathable materials out there. Its an excellent all-around rain jacket and would serve you well.
Or, theresMountain Hardwears new Amalgam ($325), a classic Gore-Tex jacket with a cut thats suitable for just about any outdoor activity. Then theres The North Faces Mountain Light ($299), another proven Gore-Tex piece thats very versatile and weatherproof without breaking the bank.
All that said, Id lean toward a simpler, cheaper, proven solution: Polyurethane coating. You can get a Helly Hansen Impertech II Jacket for $75 and you will never be wet, not with impenetrable PU. No, its not all that breathable, but when its cold and wet, how much will that matter? It also looks pretty good and is a bit stretchy.
Id actually eschew the outdoors/hiking stores, and get to a good marine-supply shop. Youll find really serious wet-weather gear that isnt as fancy but is probably better-suited to Alaska than some things youll find at an outdoors retailer.