What really annoys me about new computers is when they don't come with a Windows CD. Yes, okay, I use Linux, but having a Windows setup on my machine is occassionally useful, so I'd prefer to have a copy of it just in case anything ever goes wrong with the machine. Merely being able to "repair" from the hard drive is no good if your hard drive gets trashed!
There was a time when I used to rifle through my Windows looking for redundant .ini files, or unnecessary log files. Anything to give my hard drive some more space. And I'd diligently defrag it once a month to get that perfomance boost.