Aside from the files, I'd first take a look at what kind of headphones you're using. Regular earbuds might be fine for most people but if you want the most out of your music they may be leaving you behind. Past that, I'd recommend either the best quality MP3s possible (320 kbps constant bit rate) or a lossless audio codec such as FLAC.
M-Audio Audiophile USB Sound card gives the absolute best performance.
iPod and mp4 have the same quality. mp4s are better than mp3s. iPod and Mp4
The best player is... ( drumroll please! ) Mookette!! The absolute best at the game!
From cursory searches it seems that only the highlights are available to download as MP3s. Perhaps the best option would be to purchase the complete cycle on CDs which could then converted into MP3s (or AACs if better sound quality is preferred) as they are imported into iTunes.
Mp3s are fairly ubiquitous and can be purchased at any big box store such as Walmart or Target. They can also be found at large electronics and appliance chains such as Best Buy. For Apple mp3s (iPods), they can also be purchased at the Apple stores. One can also find mp3s online at Amazon and eBay.
itunes
Randy Rhodes was the absolute best guitar player Ozzy ever had without a doubt.... Nuff said...
The Pioneer FHP8000BT has a great sound according to various reviewers.
the best site to go on is called beemp3.com, it has loads of free mp3s to download
Panasonic and Phillips have plenty of boomboxes that play mp3s. Most electronic stores, such as Best Buy or Circuit City still carry them, and still should be cheap.
The best brands of DVD players to use for a DVD player surround sound system will be brands listed as a home theater DVD player. The home theater DVD player is specifically designed to make the most of the surround sound system.
In so far as you can call any portable cd player an audiophile item the Akai PD-X73 or Optimus CD3400 gets the best reviews.However it's not made any longer.It's the only portable Stereophile ever liked.