I have a 4 year old laptop that I was looking to discard because XP had ground to a halt on it (yes, even after a clean install - all the service packs and updates add up). By putting Ubuntu Linux on it about 2 years ago, I revived it. It's running the latest version of Ubuntu - the great web browsers associated with it, and is very fast.
I will have to replace it eventually - wear and tear will take its toll - at that point, I'm going Mac.
Regards, Ivan