Audio Technica ATH-M50. They're really nice.
Good isolation, so I can use them when recording. Deep bass, so I know what's at the low end of my mixes. Excellent detail for editing and getting the settings just right when mastering and mixing. A jack of all trades - outstanding value for audio hobbyists.
I use an E-MU 0404 USB for editing and production work, and an E-MU Tracker Pre for recording. They work well and the converters are the best available for the money. They're the no frills high quality solution.
As for the monitors vs headphones debate...
To some degree it's a matter of personal preference, though I don't entirely agree with that viewpoint. Headphones can offer a level of detail that is not obtainable through monitors. Also, headphones can offer a wider frequency range for the money, by far. For the money, in the $100 headphone vs $100 monitors category, headphones win. Hands down. Really the competition isn't even remotely close.
That said, mastering and mixing on headphones is a bad idea. It's too hard to get the levels right. Headphones have so much detail that some parts that are perfectly audible over headphones completely disappear into the mix over monitors.
Also, speakers are better for casual listening, movies and such. Wearing headphones is a chore sometimes.