When's the last time you did a complete computer scan for spyware and such? I know that iTunes likes to run three or four different things at the same time, and if it's having to compete with any other system processes then it's going to be bogged down.
Of course, there is the other problem of YOU'RE USING iTUNES! Winamp is free dude
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Sage knows our mythic history, King Arthur's and Sir Caradoc's
She answers hard acrostics, has a pretty taste for paradox
She quotes in elegiacs all the crimes of Heliogabalus
In conics she can floor peculiarities parabolous
-C'hi