I have a Samsung YP-F1 512MB player. They also have a 1GB version, but the local store only had the 512MB in stock. Paid around $100 for it. It plays oggs flawlessly, I've had it since January. Has radio, voice recorder, etc. Works great.
My only complaints are that 10 hours of battery life is just a little skimpy, only a little though, and that the charger/transfer uses the same port as the headphones, so you can't charge and listen at the same time. I really like the metal clip on it, I thought I wouldn't, but I end up clipping it to my collar a lot and it stays out of the way. I think it's locked up once on me.
This replaced an Enox EMX-900, which I had from August to October of last year. The battery died. It was an import from Asia, because you couldn't get them here. I liked that it had a built-in USB so I didn't have to carry anything else. Then I realized that with it plugged directly into my laptop it was likely to be broken. That didn't happen. The user interface on it was slow and sluggish, and the thing would hang on playing about 5% of my oggs. It did have 1GB in it though.
efm has a iAudio F1 with 1GB that she's had since November of last year. It also plays oggs, and is a bit bigger than mine. It's shaped like a little race car, if that's important to you. It has a nice OLED display, where the Samsung has an inverted LCD. She's really liked her player. No problems with it. I think it has better battery life than the Samsung, but I wouldn't trade the small size and the metal clip.
I will say that I find 64kbps oggs sound acceptable to me, where 64kbps MP3s do not. 128kbps mp3s are the lowest quality where the codec artifacts don't bug me. So, a player that can do oggs gives me about 2x the capacity of a player that does mp3s only.
If I were to buy a new one today, I'd consider the Apple Nano running the rockbox firmware which does oggs, and has 4GB, but not very good battery life, and is much more expensive than the samsung. If my samsung died today, I'd probably just buy another one.