Daily, from 25th NE to the U Bridge. On days when I want to spin, I'll hit the B-G over to the Ship Canal Trail (via Fremont Br) and then Interlake Tr / Elliot Bay Tr to downtown. Early in the morning, there's almost no traffic, ped or otherwise.
I really dig living so close to the Burke - definitely a deciding factor in buying my house. Having a bike highway - wide, no cars, few stops - is a great thing.