Knock on wood, I have never spent enough time in an airport to care about a lounge, but for future protection I think I might join the Alaska Boardroom. There is no initiation for MVP Golds and the annual cost is minimal.
The real benefit of being an Alaska Boardroom member is, however, that when you fly Northwest (dramatically increasing the time one might spend in an airport), you have World Club priviliges.
The most recent NWA mailer included a promo offer for World Clubs International for $50 for two months. That is so cheap that I think we'll give that a shot to cover our late spring/early summer foreign travel. With luck we'll never get to use it.