This is probably blasphemy...but I like Pledge. Been usin it for years. Spray it on the fretboard sans strings and scrub it a little with a soft terry cloth towel.
When you're done, it's got a nice lemony smell and it doesn't seem to pick up dust as fast. Plus it's got a nice thin coat of wax and oil on it to protect it a little.
Work on my furniture too....
