You had me until you said sound cards. There are pretty decent class compliant sound cards that are darn cheap. Then there are the USB and Firewire equipped mixers. Both Dj and console style. And at the high end we get UAD and Apogee boxes with open configuration architecture that allows different output modules to be fitted.
But then I have had a MOTU 828MKII since they came out. Still works pretty much perfectly from any Mac.
And then I gotta say there are some really nice monitors from boring old Dell and HP. May not fit the "style" of a mac, but they have really good color gamut and accuracy.
I think we mean the same thing though. First monitor: yes, there are a few very good desktop monitors available that work for photographers. They are expensive but do exist. You always have to watch out for various compatibility questions on Macs though from all I've seen so far. On laptops on the other hand monitor quality and real estate has been dropping over the last few years. The retina models sure look nice but don't have good real estate when running in native resolution. Plus they're shiny and I can't stand that. The old 15" and 17" inch hi res matt options were nicer but are old news now or have been discontinued. That's why I still do my mobile photo editing on a very old Thinkpad with a really nice screen that nobody has anymore.
Sound cards: yes, there are options. Either old USB technology or Firewire - which I much prefer but has been declared obsolete by the geniuses at Apple.