Although I do still run a Logitech Squeezebox for my hi res music files, my favorite and least troublesome system has been my Sonos.
I realize that the Sonos has its limitations. It only does 16 bit 48khz files at most, but man, in terms of ease of setup and use, it can't be beat. I have mine pulling files off of a Synology NAS, so I don't have to leave a computer running and I've never had it do anything freaky requiring a reset. The software is also rock solid.
In terms of the "total package" the Sonos is really hard to beat. It is also compatible with a broad range of file formats.