I love my ADDIEMs, they're comfortable (more so than better-sounding IEMs), light, easy to wear, and I reliably get a great seal with the large tips. The cords are totally not microphonic, too.
When that's not enough, I pull the filters out of a pair of
Surefire EP-4 Sonic Defenders, and cram the driver into them*.
There's some isolation.
The bass isn't
tooth-loosening, but it's satisfying. I paid full price for them the year they came out, and haven't been tempted away from them in any serious fashion. The Bowers & Wilkins C5 sound moderately better, but they're less comfortable, start to hurt quickly, and are
very picky with how they fit. Getting them to sit down, shut up, and seal my ear canal means they're not worth using if I'm moving around, and they hurt if I use them too long. This is a shame, because they're so much of an object lesson in that there's more to an IEM than just sound quality.
*(FutureSonics' Atrio, and Shure E3-sized IEMs take better to the Surefire tips, but they tend to lack a button or microphone, and I'm really spoiled now.)