[jonandabby]

I recently lost my CX-400 (Mk1) earphones on the train, so I'm looking to start over....

I use my Ipod mostly on the train. It is used about 50% of the time for movies on a laptop, and the rest is split between music and podcasts. I'm not willing to spend more than 100, mostly because I keep losing them. The priority is good sound quality AND very good sound isolation.  Because I commute with them and they get knocked around in the briefcase a bit, not having really awful build quality is probably an issue as well.
 
I do not care even a little bit about how they look - I'll be wearing them on a train, and anyone looking at me is an irritant, so they should not be rewarded by looking at cool-looking earphones.
 
From wandering around way too much, it seems like some of the more popular options are:

CX-300-II
CX-400-II (I'm a big Sennheiser fan, but hated the 400 because of the short cord.  I know the II doesn't have this issue)
Klipsch Image S4 (CNET loves it)
Etymotic er6i (Maybe not so comfortable for commuting?)
SE115 (a knock-off Shure?  Is it worth it?)
Creative Zen Aurvana I and II (although the #1 doesn't get much love on here)
Super.fi 3 (not sturdy enough?)
Super.fi 4 (what's the difference between this and the 3, anyway?)
 
Is the CX-300/400 (II) still the way to go in this price range? Or are there better options out there in the last 1-2 years?  Is there anything else I should be looking at?  Are any of these viewed as better at sound isolation? 

 

[Raguvian]

The ER-6i with foams will block out pretty much anything. The tri-flanges are also good for isolation but they hurt my ears (especially my right ear).

 

[RuckDive]

Just a note...if you're considering the Klipsch S4s, I'd throw the Monster Turbines out there... They're usually overpriced at around $160, but can be found for $80 here.
They're "Open Box" meaning opened up but never used. Great return policy as well!

 

[gknix]

How bout look in to the head-direct re0 as well?
if isolation is #1 priority, how about a used er-4s/p?

 

[aconteceu]

I have SF4 and I love it, but I'd vote for Fischer Audio Silver Bullet for your purpose. Very isolating with the thicker stock tips in medium size without deep insertion. Also the Bullet has enough bass for the train environment, while still being well balanced. It's also nice with voice sound files.