I have a Sennheiser
Don't expect them to wipe out all the background noise. I have a set of Sennheiser PXC150 from pc world that I wear when im driving the van around. What I like about them is that they are small enought that other drivers / police won't see them. no point in having great big cans and draw attention!!
One of the interesting side effects is a noisey van like mine, is that I can hear sirens far better than without.
Biggest downside and something that wasn't mentioned on the test is that if you have a mobile within 3 feet of your headset you get the du-du du du-du du du sound similiar to when you put your mobile near a radio / speakers. Only this is amplified. When im driving through Bristol and going through so many cells I often have to turn off the mobile because the mobile is busy talking to the masts that you can't hear anything.
Be aware that these (or at least mine) don't totally block all the outside noise so your not going to put them on and then get total silence. It tends to block out the high and low frequencies so you will still hear some road noise / mid range hum / the car radio / naggin wife.
Overall im pleased with mine (about £80). battery life seems to go for ever on 2 x AAA. Quality is good enough for my needs, but may not suit those who are complete audiophiles.