I've read threw a few of the older MP3-player threads, but I am looking for something that is small, light, and under $100, if possible. It will be for my brother, who likes to run, and that is how it will be primarily used.
Any cheap flash player sounds about right then. Creative do some nice sounding ones you can probably grab for under $100 these days. Google for Creative MuVo TX, you can probably grab one of the smaller capacity ones.
I have a SanDisk DAP 1G player. It's held up to working out with it, snowboarding (gotten it pretty wet a couple of times) and commuting on my motorcycle with it. I would highly recommend it. I'll be selling it soon to get a Nano, I need more songs.
I use an iRiver Flash player and it has held up just fine. The joystick control is a little small, but once you learn the diligence of using it on the run (literally) it is a functional player for the price.
I just bought the Creative Labs Zen Nano Plus. Its a 1GB flash player with FM tuner and I got it for $125 total. They make a 512KB version that is under $100. Not sure if its the "best", but it does the trick and I like it a lot. The thing I really like about it is its drag-n-drop. I don't need to use any proprietary software to download songs to it. I plug it in and it shows up as a drive. About the only thing that it lacks is the ability to create seperate playlists, but at only 1GB, its not like I'm going to have a lot of room for multiple playlists. I bought it for working out, and the only music I like to work out to is hard and fast, so I'd only use one playlist anyway.