All iPods have pretty mediocre sound. Not the worst but a long way from the best.
Sony does indeed have better sound, but I keep away because of the restrictive software.
Sound quality is not just about the equaliser. It needs to create a clean accurate signal and also pump out enough power, particularly if you want to drive quality headphones
iAudio make the best sounding players at the moment. The X5, X5L, U3 and the new iAudio 6 are their best players, depending on how much capacity you need.
If you want a hard disk player you might also look the the Creative Zen Vision:M, which is an excellent all round player.
In flash players the iRiver U10 and the new Sansa players look very pretty. Nicer than the Nano I think. I'm not sure about the sound quality of Sansa, but I know iRiver is good.
You mentioned 2 very different devices. The first thing is to decide how much capacity you need.
A 30Gb hard disk player is enough to carry round most people's whole collection, but they are larger and drain the battery more.
A 2Gb flash player is enough to store about 20 cds at a decent bit rate, and you can swap things out whenever you need.
I?m looking for an mp3 player. My candidates are the apple ipod and the sony nw-hd5. I?ve read that sony nw-hd5 has a 6 band equalizer so it may have better sound than the ipod. I would like to know how true this is. I?ve also heard good things about the ipod, i like the design and the capacity. I would like to know how reliable is the ipod and how good is the ipod nano(design is awesome). Thanks in advance for any reply.
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