I shall "rephrase" that then
1gb for Windows XP with a real-time memory hungry internet security suite such as norton, 16 programs in the task bar, including a p2p sharing program, 3 instant messangers, 3 music players even though only one is playing music.
See similar for vista.
Vista with trimmed settings, and no internet security software, just a non memory-hog antivirus will run well at 1gb. It certainly can use 2gb though. Xp will run fine at 512, even 256 if you don't have an internet security suite loaded.
It is just better to be prepared than to come up short.
256mb is more than enough for "Windows XP"
Problem is, very few people just run windows xp.....
Sorry if I went heavy on the recommendations. When you are at a realtive's house with a 256mb windows xp machine with norton, real player, quicktime, limewire(/sigh), AIM, Yahoo Messanger, and a few other programs that they "Won't take off, because they need", and trying to show them ways to speed it up.... you want more ram.....
Also windows XP has had numerous patches, updates, and so have many other programs that run on it. Updates can increase ram usage and bloat the ram needed for the system. Virtual memory can adapt to most of this, but it is much slower
Sorry if caused any problems. I just thought its better to advice a little higher for expansion, and possibility of lots of programs running. The PC with 16 things in the taskbar, and norton internet security is "just for internet" the same as a machine with only internet explorer/firefox, avast, and nothing else loaded on it. Yet, one runs smoothly on far less ram than the other.
As far as brands go, Toshiba seems ok. However I have had friends who had lemons with them.