Music playback "skips"

[Strygun]

Hey folks,

I've been having a problem recently with my music playback. On my computer, I have all the songs that I own in mp3 or m4a format. When I play them (using any software... including WMP10 and iTunes7), there are random "skips" in the songs. It sounds exactly like what happens when a CD is lightly scratched. It's not a repetitive-playback of the last second like a deep CD scratch, but just a "hiccup" in the playback.

Now, here's what I know:
It happens in both WMP10 and iTunes7.
It doesn't happen in the same place in the song every time.
My computer is "idling" other than just the music program. (I.E., no major tasks running.)
It happens with both CD-imported music and iTunes-downloaded music.
When I noticed this problem, I updated my sound drivers thinking that was the problem. (it wasn't.)
A few months ago, it never happened. Within the past month, it's become regular.

Any help?!