To start off, I've been using the XD200's for about 3 years now. They are a very cheap build. Actually broke one pair and went and ordered another. For $15-20 bucks new I think they are a fairly good deal.
I mainly use them with an Ipod Classic 120 GB. To me, they sound amazing(for the price mind you). I've listened to plenty of cheap headphones which can't handle multi-layered or metal music, but these seem to do a sufficient job. Sometimes the highs I think can get a little piercing, but nothing major. Definitely a step up from the XD100's.
Funny thing is that if you press them to your ears, the sound is very muddy. They just have to sit on your head.
Any other impressions of these? I paged through the forums and found older threads. Are there better alternatives available now to these, for the same price?
I love the way these headphones sound, but it may just be that I have grown accustomed to hearing my music as channeled by them.
Here is a link to a now defunct blog that has an excellent write up on them:
http://phonephile.blogspot.com/2005/01/sony-mdr-xd200-headphones.html
I just really like these headphones 
Current set up: ALAC->Ipod Classic, Foobar->Sennheiser HD280 Pro, Sony Japan MDR-V6's, Sony XD 200's, and a pair of yamaha earbuds(which I regret, very flat)
Total Bithead coming in the mail...
