If you have an older PC running Windows XP consider that upgrading to iTunes 7.x will likely result in iTunes running more slowly for you. Overall it is less responsive. I prefer the older Aqua style interface appearance to the new drab gray style. For some reason the Volume Logic 1.31 plug-in is no longer working, a quick Google search reveals others reporting this issue. My iTunes Library was also rebuilt after installation however there seem to be no ill effects so far. If you need the newer iTunes features like iTunes Plus then upgrade, otherwise it may not be worthwhile. (My PC is an Intel 2.6 GHz, Win XP Pro, 2GB RAM).