If you want a pedometer, you can go to McDonald's and order that salad that comes in that huge box. You'll get a bottle of water with your salad and a complimentary "stepometer". I read the directions while I leisurely ate my strawberry sundae (just kidding, he he he).
I also would recommend a GPS unit. I got myself a Garmin eTrex. It's big and bulky, but it straps around your neck. It can tell you how far you've gone, how fast you're going (very accurately...more accurate than the speedometer on your car), which direction home is (which can be helpful if you live in the country like me and want to do some walking off the main path). It can also mark trails that you like to walk on, sites that you've found (drinking fountains, restrooms, etc.), sunrise, sunset...these things are cool.
If you still want to go with a pedometer and don't want to go to McDonald's, they have pedometers out there that are functional. I got mine at Fred Meyer. Try to find one that will let you input your stride (both in walking and running distance). I've often wished mine had a stopwatch on it. Mine cost $15 on sale.