Your question is asking too much Whats the difference between apple and brick Ones good for cooking the others good for making homes. Both are good for what they are used for but some arsehole will always favour one over the other. I hate the ethos of saying blindly xyz is better than abc. Sorry if this offends but you will get over it with age. The best reply to your question is that Windows was written for the mass home market, linux wasnt. - Three out of three large corporations (Philips, Atos & EDS) ive worked with banned linux from the network via its security police. - Both Linux and XP can be tweaked and bloated or cut down to a core. - For a usable (as you know it) home system on a P2 455 - Gentoo used 120Mb, WinXP 190mb. - From experience both systems update as much as each other but linux will normally be updated quicker.