Pros: Relatively cheap (~$50), good noise blocking, 3 sizes of rubber cushions to fit different ears, durable, light-weight
Cons: In-line mic only integrates with recent Apple products, sound cuts in and out when jack moves slightly
I bought these at the Apple Store (had a $20 gift card, so I only paid $30+tax, though they cost about $50 at the time). They work okay for blocking out annoying treble and mid-range background noise when you're listening to music, but low-pitched rumble (e.g., airplane or subway engines) will still make your travels noisier than you'd like. No matter, just crank the volume a notch or two higher on your listening device, and you'll get pretty good sound quality for earbuds in this price range - I only gave it 3/5 stars for audio quality because I know that higher end headphones, especially over-ear head sets will give you far superior bass response and background-noise-blocking - (like the Bose QuietComfort Series.)
These headphones are great for running/exercise - they block out enough noise so that you can hear your music, but not so much that you're in danger of getting hit by a bus because you don't hear it coming. The C-shaped, over-ear pieces are made of a satin-y rubber material that has enough flex to it that taking these buds on and off is easy, and wearing them is comfortable even if you're sweaty. They're also quite durable - I've absent-mindedly sent these through the washer and dryer, and they still produce pretty good sound. I can't really judge the microphone, because I've never used it. I have a Motorola Droid, not an iPhone, and the inline mic and volume/pause controls are not Droid-compatible. I'm assured that these work with recent generations of the iPhone - I know that the volume up/down controls work when plugged into my MacBook, but they do not work with my older-model iPod. The headphones will work fine with all of the above, just don't count on the mic and controls if you're not using a recent-generation Apple device.