If your primary listening is with a digital front end (CD, DVD, DVD-A, SACD).....you'll probably want tubes there to soften and fill-in.
Translation: to distort and embellish. Rubbish! 
tee-hee, I thought much the same, oh, maybe up until 3 years ago. But there is something more than just pleasing distortion that are tube signatures. Namely, from what I understand, they are an open circuit (a vacuum, which is the principle of how tubes operate, is an open circuit).
Transistors open and close, combined with sampling rates (not
analog-ous, but digital approximations of sound), it will often make for a steely presentation as your mind has to work hard to fill in the gaps. Tube gear, with such digital approximations such as CD, have at least an open circuit so that your brain doesn't work to fill in the blanks nearly as much. So, CD sounds more 'relaxed' or softer to the ear than with solid state gear. This was explained to me long ago by someone far more technically oriented than I..
Meaning of analogous (adjective)
similar; parallel; comparable
The higher sampling rate digital technologies, DVD/DVD-A/SACD, suffer
less from the need for your brain to fill in the blanks...and may or may not sound better using tubes. Like those who enjoy vinyl, tubes become more of a
preference than a necessity.
We're all rather different in so many ways that any generalization is apt to be wrong in some way....but it is largely the case that using tubes will soften and help the fill-in with CD playback.
You may try to fight the tide of reality,
I did for years thinking much the same as you, or you can listen for yourself and decide. No lost sleep for me either way, Brian

John