Alright, that straightened out my confusion between the K601 vs K701. That was a nice sum up, pretty much a mini review.
Yeah, I think the HD558/HD598 would definitely be my best bet. In fact, I'm nearly convinced to buy! Problem is, HD558 is $180 and HD598 is $250.
(One of the guys from Sennheiser mentioned yesterday the new HD598's are shipping out with a new, stronger headband material to prevent cracking in future).