Trying to Access iTunes Store Causes Quit.

Every time I try to access the store, iTunes will "quit unexpectedly". I can access my account page through the Store menu, but as soon as I click Home, or try to search for something the progress bar gets about 3rd of the way and iTunes will quit.

The only recent change I've made to anything is installing 10.5.3

Any ideas?

Download OnyX, if you don't have it. Run the maintenance scripts, repair permissions, cache cleaning. etc..(good idea after updates)
You can also look for corrupted preferences files, with OnyX.