There's a lot of not-too-good advice in this thread, mixed with good, in my opinion, relative to the quality of what comes out of the 810. The original poster needs to understand that he needs a system that fits HIS needs and HIS ears, not the theoretical prejudices of audiophiles and engineers. Lots of people find iPods satisfactory, which is why so many own them. Lots of audiophile types make iPods work for them under some circumstances, by various dodges. If, however, you run iTunes music through them, encoded at a very low rate, the result ain't too good. That is, garbage in, garbage out.

That said, my 810 doesn't sound horrible run into my good headphones, which cost twice what the 810 did (and aren't high-impedence, nor do they demand a lot of power), with good source files. Things could be better, but they could be a whole lot worse. I don't think the data specs of the thing are sub-CD quality--16/44.1--and probably the amp is about what you get in any mp3 player these days; that is, not audiophile, but adequate.

The real place to be finding out this stuff, if you want to know practical stuff about amps and headphones (rather than the specs of the 810) is at http://head-fi.org org
If you prefer to hang out at the other end, with the guys who think everything is inadequate garbage, check out http://www.head-case.org/
Your choice. :-)