iPhone mapping app?

[Turtle Dude]

What is a good iPhone app for showing maps and cycling routes, without having to keep downloading over 3G ? - i.e. you can download the maps beforehand.

I know of Memory-Map, OS and MotionX - any of these any good, any others better ?

 

[barongreenback]

Viewranger has OS maps but is a bit pricey.