Monster Turbine Pro Gold + iPhone 3gs

I'm lookin at gettin a good quality set of  IEMs for use with my iphone 3gs and needed some advice. 

basically new to the whole audio world, and i appreciate any advice. 

on the recommendations of head-fi'ers, I recently got myself some denon d2000s and they are perfect for my listening tastes; lovin them. 

I got the majority of my library up to flac or 320s but would it be a waste to plug the MTP into an iphone?  could the iphone drive 'em properly?  are iem's really that hard to drive?  if the iphones no good, what would be a good portable?

(again, see line 2)

Thanks for any advice

cool, thanks for the reply.  appreciate it.  I'll def be checkin out those portables you mentioned.

that J3 looks to be pretty sweet, I've been readin up on it the last 2 days.  I'd like to keep jus the iphone n a good set of iem, but dont really want to invest in a good set if the iphone will only bring out half of what they are actually capable of.