I am planning to buy leopard little after the macworld when 10.5.2 is released. But I want to make sure that I have enough ram currently to run leopard with minor hiccups. I have around 768mb of ram, but I'm planning to upgrade 1.25 gb in the future after i get leopard or before leopard. I just reformat my external HD to Mac OS X HFS Volume. Just incase when I back up my internal HD and if I have any problems installing leopard