I'm basically looking for something that's easy to use, quite small (credit card sized even) has a display that's not necessarily big, but readable. and does not use itunes :P probably around 1GB - 2GB (or more)
Here's a link, http://www.anythingbutipod.com/ that has good reviews on DAPs, though I haven't bought a dac in ages, I can't tell you my suggestions. I bought a MuVo for my dad 1-2 Christmas a go. It functions well, and its good for its price. Good luck on finding one for your dad. :)
I have that Zen Nano Plus myself in blue. It's about the size of a lighter, the text is just right. It has a nice blue backlit screen. The sound is really good even on the cheap earphones that come with it. The battery life is good. I've listened to it many hours on a single AAA battery. It comes with it's own software to upload music to, but I personally just plug it in and drag and drop my songs right into it. The only downside to this product is that the FM tuner is crap. You can't manually tune in stations. It seeks them, stores them and only lets you listen to those stations untill you do another full seek (but why would you get an MP3 player to listen to FM radio?)
I would reccomend a Zen of some sort. Take a look at their site, they have some really good players, and not too expensive. I have a Zen Creative Microphoto (8GB), it has shitloads of features and it was cheaper than an iPod by miles.
This is a really nice one from sony, It features a bright oled screen with 3 lines, great for reading what track you are listening to. It looks nice too!
If you charge it for 3 minutes, you will get 3 hours of time. 1 min charge = 1 hour life
the text are not as large as I wanted it to be, but it's quite readable and bright as the sun :P
my dad saw me bringing him the box and he nods in approval :) he's a busy man, but give him a few days and he'll eventually nag my mom for hogging the mp3 player :D
one thing though, as the v plus charges from USB, I should buy him the standalone adaptor.
I would recommend the iRiver Clix first generation. It's a good player, gets fm radio, pictures, movies, text, voice recording, and it's really easy to use. I got mine used for about $80.