i'm gonna recommend the maverick audio tube magic d1 DAC/amp combo, as it is within your budget. even though it is my first real desktop DAC and headphone amp, i just got mine and i am very impressed. it really makes my headphones sing. it has coax, optical, and USB inputs, so it is pretty flexible to whatever sound card you have. i prefer to not use the USB though so i can still manage sound card effects. it has stereo and headphone outputs.
that said, i have heard the uDAC before, and it is a good product, but it can't really beat a decent desktop DAC, unless you need the portability for use with a laptop, for example.
now you say you want the unit to be able to eventually drive high-end speakers, and probably at $200 you are probably limited to self-powered speakers here, but the mav tube magic d1 should be able to handle them well. although if you go actual high-end, i think you would need to upgrade your DAC again. also keep in mind that you would need another separate amp to drive better speakers. the nice thing about the tube magic though is you can use it as a pre-amp if you eventually do get another amp. personally, i am happy with self-powered speakers through the tube magic. it sounds good enough for my bedroom at least, until i get a dedicated sound room.
as far as alternatives in your price range, i hear the zero DAC is good, and audio GD makes good DACs too. g'luck!
