Hi there! I bought my iMac just a few months before Apple released Leopard, and I never bothered upgrading. What exactly do I have to buy and how much will it cost for me to upgrade to Snow Leopard from 10.4.11?
I upgraded my Leopard 10.5.8 to Snow Leopard last year, it cost $29. If you upgrade from 10.4.x Tiger, you should buy Snow Leopard box set which include iLife 09 and iWork 09. For more information you can read Applestore Snow Leopard upgrade offer
You should def get Snow Leopard, its much faster then Leopard.. but I don't think you'll see a significant difference in performance from tiger to snow leopard.. but I guess 10.6 has many more features.. and it truly utilizes over 4GB of memory