I have over the past few years now owned two mp3 players, both by Rio audio (formally Diamond Rio). My first one was a Rio 600, which has since been replaced by other models, my one complaint against it was the quality of the headphones and that was an easy fix. When that one got too small (it held like 7 songs, it was a really tiny player), I bought off ebay a Rio Chiba. My chiba has 256 mb (right now I have a mix of MP3s and WMAs for a total of 70 songs) and has a slot for extra memory cards (SD format, like the little square ones for digital cameras and such). I love this player, it even has a FM tuner that works fairly well. I paid $130.00 dollars for it, but could have paid $100 had I been more patient. Rio also makes larger and smaller players for many budget and memory requirements. I personally would recomend this brand, but having never bought another brand or delt with Rio'* customer service.
Rio'* website if you want to look at their selection : http://www.digitalnetworksna.com
(then click on the Rio button)
If you have any questions about the ones I mentioned, feel free to ask. I'm sure everyone has their favorits...this is mine