That is a pretty loose question for me.
there is a reason I have so many bikes. I love it all.
so the answer would have to be.... WHAT EVER I happen to be on at that point in time.
I ride everything from Trials (big ass rocks), to dunes, to desert, to street, to mountains, to singletrack, to ........................
Most fun EVER on a motorcycle. The dunes, the BIG dunes.. (not that origon toy stuff) after it just rained... on a open class bike..
The only time I ever wasnt having a BLAST on a motorcycle was on dirt roads in Mississippi, after it rained. the mud there is like a greased Ice rink, and the main problem, is its the EXACT same color as the dry dirt. so you will be booking along at 50mph, and before you can blinnk, your sideways both front and back tires sliding with ZERO traction, no responce, and heading into the woods..
but... Id still rather be riding on those roads again than playing Xbox, or going to the movies, or what ever the hell it is youth these days do...