I found that upsampling 16bits/48khz LPCM DVD tracks to 24bits/86khz often produce better sound than originals. The beauty of computer-based audio system is that DSPs like upsampling is possible on the fly. All you need is a computer with built-in DVD/Bluray drive, a USB-based DAC and a good quality headphone set. That's all you need to enjoy high-definition audio. If you have old-style analog equipments, you will miss the high-definition audio. Computer-based audio systems offer much better sound. When you select a DAC, make sure that it is genuine and simple. Genuine means it supports 24bit and 192khz by hardware. Not by stream conversion. Simple means hardware does not support non-essential features.
There are some upsampling plugins available. One is ffdshaw which work with WMP. Another one is for foobar2000. Unfortunately foobar2000 sounds not very good. So upsampling doesn't show difference. So I mostly use ffdshow on WMP.