Hello,
I'm using a E-MU 1212 PCI sound card in a Windows workstation and notice when wearing headphones that there's a faint but irritating white noise when dragging around windows and other UI manipulations. The home-built workstation is less than a year old (parts are fairly new), and has a huge power supply, so I don't think that's causing the noise.
 
Is this something common for internal sound cards as compared to perhaps break-out boxes? Or do these make similar noise? What would be the best "upgrade" from an internal sound card?

I don't know how you are getting audio in and out of the E-MU, but, if I were you, I'd be looking for earth loops between the PC and the associated kit. Make sure that cable screens are earthed where they should be and are discontinuous where otherwise a loop would form. Earth loops near PCs seem to be phenomenally good at picking up "mouse move" noise.

Thanks for the suggestion. I found that a connection in to my PC motherboard sound was causing it (the mobo sound is poor quality and picks-up noise from system). I unplugged the connection, and now it's quiet.
 
Now, if I can just get my E-MU card to not sound distorted after waking from sleep!

jpaul
 
Now, if I can just get my E-MU card to not sound distorted after waking from sleep!

Stop using sleep.