Unfortunately, headphones are a very personal decision. One set may sound and feel great to one person and another might hate them.
First you have to decide if you want earbuds or over the ear style. Then, you can begin to weed out the hundreds of types by reading reviews. I personally have been very happy with a pair of JVC earbuds that fit into my ear canals with a soft rubber tip which rejects ambient noise. They are made by the same people who make the Creative brand.
I tried a pair of Bose over the ear noise canceling headphones and I couldn't tell the difference in sound quality or noise rejection between the very expensive Bose and my JVC ones which cost less than a quarter of the price of the Bose.
I have been a professional pilot for over 40 years and my hearing is shot from noise exposure. Regardless which ones you buy, be sure NOT to turn the volume up on your iPod too high (set the volume limiter) or you will suffer the same kind of hearing loss and ear ringing that I suffer from now.
The sky can be the limit as your budget is the most important factor. I am personally listening to my touch right now thru a $500 pair of Shure SE530's but this might really be out of reach for you. The good news is that there are good options at any budget. So once you establish that then we need to move on to what type of use are they for and what generes of music. I could go on and on, but I am typing on my touch right now. So for starters give us some more info like what I covered here and then we can refine your search.
I also dont see what the bad (really bad) reviews about the bog standard headphones that come bundled with the ipod/phone. Not bad at all concidering they are free!! Saying that tho the sound quality isnt amazing but pretty good regardless.
I am not sure how much you have a budget. But if you consider really good headphone, you have to invest more than $150 in my experience. By the way, don't buy Bose. It is lame, and overated product. Sound fairly ok. But it is all warm with no excitement. I hate it. I recommend ultimate ears. They really make a good piece of it. I have Ultimate ears super fi. 5vi for my iPhone. Sound is incredible. It is about $190 without tax.