So my "partner" isn't actually a person, but I love my Nike + Sportband. It tells me how far I've run, my pace, my time, how many calories I've burned, and doubles as a regular watch when I'm not running. It's really easy to switch between the different modes while I'm running. I usually watch my pace the most during my runs, but I occasionally check to see how far I have run. After I calibrated it, the sportband has been really accurate (it was pretty accurate before - only off by .1 or .2 miles).
You can also detach the face of the watch and plug it into your laptop to upload your runs online. I really like being able to see my progress week to week - definitely keeps me more motivated. You don't have to have a Nike + Sportband to be a member of the Nike + community. Instead, you could just buy a sensor and download the free app on your iTouch or iPhone. I run with a iPod nano (I know, old school) on my arm because I don't like carrying anything while I run. I like being able to look down at my watch during my run and check my progress. However, you could also do this with your iPhone or iTouch as long as you don't mind carrying them.
For $59.99, you get the sportband and the sensor that goes in your shoe and tracks your progress. I don't have Nike shoes (I'm a huge Mizuno fan), but I bought a little pouch that attaches to the top of my shoelaces. If you have Nike running shoes, there is a specially designed place for the sensor under your left heel.
I highly recommend this for any runners out there! It's a great, basic running tool that's not a huge investment (some running watches can be $200-$300). I wish I could track my non-running workouts, but I'm happy with what I have right now.