Count me in as another Rio 500 fan.
Last Summer Best Buy had a deal on a 128MB Rio 800 for $100 - an incredible price. I bought one and ended up taking it back.
The 800 was a nice unit, and it has MUCH better sound quality than the 500 for sure.
What it doesn't have is a dial - and for me, the dial is key. It makes it SO much easier to change volume, flip through menus, etc.
I think the 500 is just ergonomically a much better design than any of the other players out there. That plus the fact that I couldn't find any software like Riositude that works with the 800, and my decision was made. I kept the 500 and used the money to buy a 128MB SM card so now I have plenty of space on the player.
It's a shame that Diamond/Sonic Blue abandoned this design and all support for the player. I don't know if the sound quality improvements in the newer players are software or hardware, but I wish I could bring them to my 500. I too will wait until I see something similar or better before I upgrade - the thing's been working for about 4 years now, hopefully it'll last.
BTW if any of you 500 owners out there are still using the lousy Rio software to transfer songs to your player, do yourself a favor and check out some of the other programs written by enthusiasts. I use Riositude basically because it's the first one I found, and it's simple and easy to use. You can find more info about this and other programs at
RioWorld