If you like easy and have lots of money and aren't worried about compatibility, the iPod is a good choice. It's actually a good device. (iTunes is another matter entirely.)
Apple, like many other large companies, is risk averse, and what that means is poor format support. No OGG, no FLAC, etc.
Smaller companies aren't so averse to risk and will include FLAC and OGG support along with others.
If you're an audiophile, WMA is one of the best formats out there. WMA lossless is excellent. WMA lossey still beats MP3. FLAC is lossless, and excellent, and open.
If you have a lot of wave files, an iPod is a poor choice as iPod wave format support is very poor.
Sony's proprietary formats are also a very bad idea.
I'd say have a look at COWON as they are aggressive and hungry. But I have a bit of an irrational affection for them, so YMMV. The X7 and the J3 look very slick. One other good thing about COWON is that they offer far better compatibility than just about anyone else out there. Oh, and battery power -- the company puts a lot of focus on that with some of the best in the industry (I could be out of date though - check some recent reviews). http://en.wikipedia....rtable_media_players
I don't know about Samsung players. Years ago their UI design was absolute crap in their phones, but they've come a VERY long way. Might be worth looking at.
Not sure about Sony.
There are a trillion players out there with no name that are really cheap. You could get one for $30 then figure out what you like/hate about it and go for a better one. MP3 players are literally disposable now.
Phones are a bad way to go. Their batteries just don't stand up enough for media playback. Especially video.
iPods have had a bad run with battery power. Not sure about the most recent ones.
Anyways, just my $0.02. Hope it helps.