Recently I've been considering investing in a high-quality pair of headphones. However, since I've never gone beyond cheapo earbuds before, I have no idea which brands/models are the best. Does anyone have any suggestions or recommendations?
For the record, I'd like to limit my budget to $150 or so.

skullcandies. They are the best headphones i have ever owned. A lot of people complain that they break easily, but i've had my current pair for about 6 months now. You just gotta be gentle with them. But they are really good quality.

Sennheiser is a brand that is good. Around the ear is preferable (most around-the-ear headphones that aren't made from glue and hair will beat most on-the-ear headphones; a caveat follows). I don't know that Sennheiser has this problem, but some "good" around-the-ear headphones were apparently designed for people with strangely-shaped heads, which causes the cups to either miss the ears or fit on them at an odd angle, so you should watch out for that.

I really wouldn't know, as I have only ever invested in cheapo drug store earbuds.

I WILL say, however, that I personally dislike around-the-ear earphones, as I find them uncomfortable and they always seem to fall off...that, and the cups never stay inside my ear. ><

In? They go... around.

Oh, THAT kind! Yeah, those are alright. I was thinking of the kind that's like a cross between over-the-ear ones and regular earbuds.