So far for me, with 2009 iMac, it seems to be "only" freezing with "Go to Current Song" or "Next/Previous" in the Get Info panes. It never seems to come out of that - I've needed to Force Quit every time, although I've never waited longer than about 20 minutes.
Note that it's also hanging a lot - anything with podcasts in particular. However, so far it's always come out of that, after at most five minutes or so.
Sigh. I use the Command-L / Go to Current Song a lot, and it's going to take a while to break that habit.
Good luck with making the 2006 iMac work. You may or may not want to hear this, but slowness with iTunes was what finally drove me to buy a new computer about three and a half years ago - and iTunes, along with iPhoto, are the only programs that are causing me much trouble now.