I have the AKG IP2 and love them. Shure makes nice expensive stuff. Make sure you get the ones with different size muffs so you can make a custom fit in your ear canal. Mine block out noise yet I can keep the music low enough I dont go deaf and I can still here what is going on around me
I use the etymotic "etykids". I think they're exactly the same as the MC5 buds, except their maximum volume is limited to a lower level. And trust me, the maximum volume on these is more than anyone should really need.
I got them over the MC5s because they were cheaper. I was at first worried about the phones being physically smaller than the MC5s... I figured since they were marketed for kids, they'd be smaller to fit into kids' ears, but that's not the case. I wear a size XL helmet, and these seal in my ear just fine. They isolate sound very well.
I have a pair of the Etymotic er6i. Love 'em. Don't have to turn the volume up, and sometimes have to turn it down. Downside is that they don't have a microphone to use w/my phone. So, I also have a set of Skull Candy, with the microphone. They're ok, but not my favorite.
Looked at the MC5s, and might have to give them a try.
I had a pair custom made at the bike show last year. I got the least expensive single driver ones and still hesitate to say how much they cost. Also, I don't wear them on the bike, only for air travel. On the bike it's strictly plugs - no music, phone, etc to distract.
I love my shure se215's. The only part I don't love is that I lost one of my self made custom foam pieces. Any one got an extra pair of SMALL foam ear sleeves that fit the se215? I will pay for shipping.