The amount of time you can use a 1.8GHz iMac G5 with just 256MB of RAM, in case your wondering, hovers at about 24 hours.
It’s a very nice machine (of course I’m sure the Core Duo iMacs are nice as well) but I’d just like to confirm that 256MB of RAM is not enough. That’s probably the case for any Mac you get nowadays. (More RAM should be here tomorrow. Yay!)