It's not a statement you might expect to hear from a successful businesswoman and arts supporter. But "unexpected" is sort of what Marita Holdaway is all about. With her upbeat, energetic patter and infectious laugh, it's not difficult to picture Holdaway on stage riffing her way through a stand-up routine. In fact, it's easy to imagine her accomplishing just about anything. What Holdaway has accomplished—a reputation for being unusually artist-supportive—is no laughing matter.

Positioned smack in the bustle and noise of First Avenue in downtown Seattle, close enough to bite the ankles of the Seattle Art Museum's Hammering Man, Holdaway's Benham Gallery...