The "father" of Ubuntu, Mark Shuttleworth, sets a goal for 200 million Ubuntu users by 2015. 200 million users would be great, because this would get software firms to focus their products also for Ubuntu and Linux in general. Hardware support will get better with official drivers releases. Linux already has great software and good hardware support.
200 million users will attract malware creators as well. Today you won't see much malware targeting Linux distros or MacOS, but as more people start to use them malware developers will roll up their sleeves and get cracking.
“[Our] goal is 200 million users of Ubuntu in 4 years. We’re not playing a game for developers hearts and minds – we’re playing a game for the worlds hearts and minds. and to achieve that we’re going to have to play by a new set of rules.”