I was given a pair of Monster buds which were quite nice but they had that sort of "bass booster" boom box quality to them.
But, I prefer the Ultimate Ears collection - I own a pair of custom in-ear molds for stage monitoring as well as a cheaper universal-fit model. They come with 3 different sizes of ear bud fittings to best fit your ear.
They will have a booth at NAB this year if you want to wait and try their whole line.
Please do keep your Apple stock ear-buds, though. I keep a pair around to cross-check my mixes because this is what 90% of the people use on iPods. So they're still good to have a pair around.