Good thread.

On my iPhone 4 I use MotionX GPS. I tried Runkeeper as well but I like MotionX because the mapping is a little better, as well as the GUI. I use it for hiking, running and cycling. One of the better features is the ability to store offline maps. This is great when you are out in the mountains and no 3G coverage. This happens even w/ trails a few miles from my house. W/ the map storage, you can just track your route. I bought a Polar 625x to track my workouts but my iPhone is WAY more convenient. Being able to post w/ Google maps and Facebook makes it easier too.1

I also use the Geocaching app, which is the official Geocaching.com app. 2 yrs ago I bought a Garmin Legend HCx JUST for caching because I liked it so much (granted I'm still around 50 caches). Now I use the iPhone app and it's much easier. I can store pocket queries and maps so that I don't have to rely on 3G coverage. I've even used it to find a few caches in Tel Aviv, Israel. Unfortunately, I didn't have time to look for any at Machu Picchu last month. Now my kids love caching, pretty much because it's an excuse for them to get toys. But it allows us to enjoy nature a little bit more.

I'd be interested in knowing about any fantasy basketball apps. I know that there are a few for baseball and football.