Wow, I'm actually pretty surprised by the replies here. I mean, I've A/B:t a lot of basses and I think the fretboard makes a significant difference. It's not a huge ground breaking difference, but still a very audible difference. But I guess it's also good to point out that I always listen to the acoustic sound first, amplified second. And it's also worth noting that I might put more emphasis on wood selection when it comes to basses, but that's just the way I see things.
Maple would be brightest, rosewood the warmest and ebony would be sort hifi version of something in between. Some could call ebony best of both worlds (or worst for that matter), but personally I don't have an opinion which is best. They're all just differend.