Sennheiser HD 555's. Love 'em. I use them for when I want the most out of my music for long-listening since they're quite comfortable.
Sennheiser RS 130's. I find myself using these almost constantly (hooked to the tv)! They're comfortable, sound great for wireless, and static doesn't usually get in the way. There's a ton of interference in my apt building. A wireless-g network is actually impossible because of it. I was forced to use wireless-n. These headphones do quite well, considering. At my brother's place, they're even better.
Sennheiser CX300's. I use these for running, mainly. For $20, they sound fine. The mids are muddy, but the lows are good.
UltimateEars TripleFi 10vi noise-isolating earphones. These certainly sound awesome. Very clear. I am afraid to use them out and about, but they have their uses.
Skullcandy stuff. Got these because I need cheap stuff that I won't mind damaging. I certainly wouldn't take any of the ones above to the barn or the Army, so that's where these come in.
Double Agent wireless headphones (they use an SD card), which is perfect for working around the farm since there's no wires. They sound ok, too... especially for $15. Lowrider headphones in white are the compact kick-around ones. They sound pretty bad, but they do the job for $10. Titan Chrome earbuds sound ok. They're mainly used for Army, as the wire is durable and they're good 'buds to beat up for $10.