First and foremost requirement: All cables must be disconnectable; nothing built-in to any component, whatsoever. Every speaker set I've owned so far has had problems due to cabling, and they cannot be simply replaced. (Instead, I have to attempt to solder them together, which results in a huge durability problem.) Obviously, this means no proprietary cables nor siamese connectors. (Multiple cables going into one connector is pretty much the worst idea ever.)
After that, I'd like something reasonably portable. All computer speakers pretty much meet this requirement (except for giant subs and 5.1's). I want to be able to pack this up and move it to another room, and on occasion, bring it to a party.
2.1 setup preferred. I don't have space for 5.1, nor do I need it that badly. Budget is around $100-200, but only if it's going to last some 10-20 years. (I have monitors and a karaoke machine with aux input that are still working just fine.) Otherwise, I'm sticking with $30-$50 sets if they're just going to break.
As far as audio quality goes, I have no real preference (in the sense that some listeners prefer warmer sound, more bass, etc.). I just want something an audiophile would consider well balanced and good for the price.
I suppose I'd be open to wireless headphone recommendations too. I'd like to be able to use my X-Fi soundcard though (something that takes 3.5mm input and USB powered at the receiver end would be great), but bluetooth is probably the only way to go when it comes to wireless headphones. Monoprice has a few I can look at, which would be good after the $23 one I bought from them broke. (I've had more cable/wiring problems than headband problems though.)
Overall, audio equipment doesn't get outdated over time the way even monitors do (I already replaced some old ones with a triple IPS set), so I'd like to invest in both quality and durability, although my budget is also limited and I don't want to spend too much.