I found WisePilot this weekend. What i like the best is it has an option of buying the app for 1 day. If you drive that amount on the navigation it's a real nice option for once in a while.
The maps are online, so it's only good without roaming. But it didn't made 100kB for 5 kilometer ride. While on my other phone (nokia n97 mini) with ovi maps on it (no local maps), it was more than 3MB for the same ride.
Just made an trial ride. It's good, nothing more or less.