[quote name='parKer']I think the KSC75 are a great choice, but seeing as how OP will be on a noisy bus, I'm not sure how they'd do. I didn't like the HD201 myself, because of their relatively large size and an amp was needed to get any substantial volume out of my iPod. Carrying around an amp ruined the portability for me. For commutes, I use the UE S.F5 or Sony D66. [/QUOTE]
Yeah, they're not great choices due to external noises, I figured that I would comment that for the money, they might as well get a better sounding phones.

I've never owned an iPod but I never ran into any issues running the HD201 on my Zens or my Cowon A2 unamped. They are a bit big for portable use tho.
[quote name='parKer']If you're not getting good isolation with the UE S.F3, then you may not be getting a proper seal. I had to try different tips and the UE mod before I got a good fit. Decent for the price, but I pitched them for the S.F5. *sigh* Head-fi...[/QUOTE]
I should've been clearer when I said the sound isolation wasn't that great on the S.F3s. They weren't that great
when compared to the super intrusive ER6i. :lol: I too ditched my S.F3s for the S.F5 Pros. And yeah. Head-fi as well.
[quote name='parKer']I also didn't enjoy the Etymotics because of the bass issue. And, I didn't like how far they had to go into your ears. :lol:[/QUOTE]
The ER6is fit a lot better with short Westone foamies. They don't extend as far but you get the same iso. Granted it still doesn't "fix" the bass tho. I still like using them for all my live albums and classical pieces as well as talk radio since the low bass is a great thing there.
I also would like to add that if you're use to 128 or 192 kbps MP3s... you're going to do a lot of re-dling/re-ripping if you get some good IEMs as the artifactings pops and fizzle will ANNOY the crap out of you when you hear them in clear detail.

You might be upgrading that player as well and down the slippery slope of audiophiles we go. It's a fun trip tho.