iTunes 10.2.2 pausing randomly (and indefinitely)

I have an iMac 2.93 GHz Intel Core i7 w/ 8GB RAM, running OS 10.6.7 and iTunes 10.2.2. My entire music library is on the internal hard drive. I have noticed for at least a couple weeks (more or less) that playback is pausing at random points in random songs. The problem seems to occur with music I have digitized with iTunes as well as stuff I have purchased. Sometimes a playlist can loop several times without stopping, but other times it will pause on several tracks. But it's never the same tracks over and over or same spots. It's really odd. I've tried basic fixes like repairing permissions and restarting the computer, but it makes no difference. I'm primarily listening to the music streamed wirelessly via Airport Extreme to Airport Express, but sometimes it is also straming to our Apple TV.

The secondary problem, which seems related is that sometimes songs will studder in identical playback circumstances as described above. And by studder, I mean that the sound just cuts out for what feels like about a second or two or three. Then BOOM is comes right back in where it left off. It's really jarring and annoying. This part sounds to me like there is a problem with the hard drive performance or maybe the speed of the wireless network. Either way it ***** and I don't know how to fix it.

Your thoughts/suggestions on these problems are much appreciated!