Useful and good are relative terms here. If you mean productive and efficient, I'll take Linux over Windows every day. Look at the awful mess that is the Windows start menu. Click start, click programs, scroll around to find the folder it's in (if you can even remember which one), click the folder, click the program. That's just to launch an application, which is the most fundamental function of an operating system. The sole function of Windows is to run programs, and it's not even efficient at doing that. The simple things should be simple to do. How about installing a program? I'd much rather sudo apt-get install foo or find it on Synaptic than track it down on the internet and click through a 10-step installer. Even if it's not available in the repo, there's a good chance there's a *.deb package on the program's site, which is still easier than a traditional Windows-style installer. Windows has the advantage that commercial games are heavily geared toward playing only on that system, and Linux is not perfect by any means, but I'll take it just about anything over Windows.