Ram, I don't give much importance to the laptop/pc/mac part since I'm only interested in the USB/SPDIF out of those sources - and between the two, I prefer the USB. Some would advocate that a desktop CPU far way from its Monitor would be better isolated than an all in one solution like a laptop. Even though I haven't used a desktop in the last 10 years or so, when tested against each other, I couldn't find any noticeable difference between the two concepts. After trying a lot of players, I ended up using Foobar with WASAPI since I was experiencing some issues with ASIO installed earlier. I strongly believe, its the rest of the chain that is important and makes all the difference - DAC, Amp & Speakers (+ IC if you indulge so)
Cheers.