Black and white is a classic color combination.

I don't think dingy would be an issue from what I know of you (you're likely to take good care of it, and you don't have kids). Also, I'm imagining that with the kind of money you're looking at spending, you'll have these pieces a long time. You won't always have your sofa(s) in the same room as your headboard, will you? Or is that typical in NYC?
For now, I have a fairly large bedroom that could use a loveseat or an armchair (I had just mounted a panel TV on the wall, ), and I spend 100% of my time in my bedroom. (The common living room downstairs I pretty much never use, it would need a lot of work first: major paint job, carpet, decent TV + stand, window treatment, that's like a 3K investment before I want to hang out there - for an apartment that I rent on a month-to-month basis without a lease with 2 other roommates. I might do it all eventually if I keep living there, the rent is low enough, but I focus on pimping out my bedroom first.)

You're right, eventually I'll probably have an apartment of my own and the leather set would go in the living room, so I'm doing this with the future in mind. It would be nice to buy a realy nice set that would last me for the next 15 years. I could put a cover slip over the piece that goes in the living room.