idc:
Hi chainrock. My Grado SR80s sound rubbish with my ipod classic. There is not enough of an output from the ipod to properly drive them. All of the Grados you mention have the same impedance, so it will be the same with all of them. My little ear bud Sennheiser mx500s sound better than the Grados. You would be better with the likes of the iGrado or Porta Pro headphones to use directly with an ipod.
Or get a small portable headphone amp of which there are many on ebay. I have not used one but the likes of Blue Jelly, the C-moy on which it is based and further up the price range Graham Slee's portable amps come highly recommended.
As to which headphone to pick the SR80i would be top of my list. When I auditioned headphones the first to be ditched were the SR60s. I dont know what the fuss is about. The 80s are not much more and sound bigger and have better clarity. The Grados are more exciting and dynamic and the Sennheisers are warmer and have a fuller sound. I like rock, indie and electronic and I prefer the Grados. But a lot would come down to comfort and the different padding the Grados have to the Sennheisers. No point in getting the Grados if you find them uncomfortable. I prefer mine with the full ear pads as opposed to the standard ones, so if you want the same you have to budget in a bit more.
I don't agree with this at all, apart from the last paragraph, and the second. Hang on. I only disagree with the first paragraph! LOL.
I have an iPhone and tried many different headphones with it. the only problem with the best ones (Sennheiser HD650) was that they were a bit quiet. You need a portable headphone amp, like my Headamp Pico, to drive them. That said, my Ultrasone HFI780 which are full sized, closed headphones sound great and my Ultimate Ears Triple-Fi 10 in-ear phones also sound great. There is a small but noticable improvement in using the Pico, but you can easily drive them with an iPhone and the difference in quality over the standard headphones and with respect the iGrado, are significant.
Go and get the best you can afford which you like the sound of. You can add a portable amp later if you need to.