I'd say for ease of use and cost / performance, a Mac mini - new or used - or HaLs server. And yes, with the right software, HALs can definitely be run "headless" with a tablet. One big advantage with HAL obviously is the after sales support with someone that not only knows his stuff and is responsive, but also has a mind to optimize for sound quality vs general computing needes. Aside from these two I also like the Salkstream / Salk server, which I believe cost a bit more than the HAL & Mac mini options.
I'd avoid a Samsung laptop - or any laptop - unless your budget is limited to one machine for both music and general use. Among other reasons you don't want a noisy sceen and potentially battery in the chassis with your music server. Not all batteries are of course noisy - depends on implementation - but I'd venture to guess that the battery implementation in a laptop is not optimized for low noise.
