I do have the need for speed
. If I was in a backcountry setting trying to take it all in, I would probably opt for hiking. For a fun day outside around Texas, I have really been enjoying mountain biking. My legs are rock hard and cardio fitness is way up. It's challenging to see if you can clear a difficult climb or make a scary downhill.
I still like hiking when I'm in the mood to go slow and look at all the birds and plants.