According to AppleInsider we could be seeing the next upgrade to iTunes as soon as next week. It is expected to just have a few tweeks here and there rather than any major additions. One are that it is hoped it will improve is the problem faced by some iTunes Store customers while attempting to upgrade certain standard iTunes tracks to iTunes Plus versions.
Users of the current version of iTunes have experienced an issue where iTunes Plus upgrades cause the software to hang indefinitely following data downloads, eventually requiring a force quit.
Started iTunes seven times now and it crashes after 3 to 5 minutes. Sent reports to Apple. Waiting for Jo-Bs or a patch….
That sounds exactly like the issues that I had. Afraid that my answer was to reintsll Leopard!