[Kdub454]

The first "expensive" pair of headphones I bought were the upgraded apple in-ears (w/ dual drivers). Those were by far the best headphones I have owned, but that was two years ago. I am now looking for an affordable upgrade, preferably less than $200. I like detail and spaciousness.

 

[oregon]

Get full size phones. You will see a MUCH bigger increase in sound quality. My recommendation would be Grado 225's, which have both amazing detail and soundstage. I still miss mine and I think I might even buy another pair after I sell my TripleFi 10. You should easily be able to pick up a pair under $170 in the classifieds forum if you don't mind buying used.
 
But if portability is a must, I don't know what to tell you. I have/had the ADDIEM's, and also Klipsch Promedia (same as S4/i), TripleFi 10, and Monster Turbines. I like the Promedia the most because the fit is very good and the remote in the cable is really convenient (same as the ADDIEM) when using my iPod. Also the sound is pretty good, though not as good as the TripleFi 10. I don't mind, though, considering it's my portable phone.
 
I'd say decide what's most important (fit, sound quality, durability, appearance, etc), then report back. Until then our recommendations won't be very useful.
 

 

[Marcus_C]

Welcome to head-fi! You haven't really given us much to go on, do you want headphones or earphones? Are they to be portable? What do you want to improve on soundwise?

 

[Kdub454]

Portability is pretty important to me, I got a good deal on the turbine pro coppers so I bought them, but since returned them because a factory defects... Something with a lot of clarity, deep but controlled bass and good highs. I'm not exactly sure how much more specific I can be.