Thanks, so 24 bit files are only downloadable from internet, and cannot be had through ripping cd's. Maybe SAcd only?
Yes, you will generally get 24-bit files from internet downloads.
HDCD discs will rip as a normal CD, but you can then run those files through a HDCD decoder which will give you a 24/44 file containing the 20-bit HDCD audio.
DVD-A and Blu-ray Audio discs should also have 24-bit audio if you rip them.
Note: Media Center does not rip these discs itself, and they're a bit trickier to rip than CD.
SACD is a 1-bit format with sample rates 64x that of CD, and they are very difficult to rip - computers can't read the discs, so it is only possible with a modified PlayStation 3 console.
You should be able to rip the CD layer from a hybrid SACD, but that's just 16/44 again.