I run everything I have on Linux. That's because I get the leftovers from the kids who just *have* to run Winnie. When their laptops don't 'work' any more, I get them and they zoom on Linux. As well, if you like to explore the sketchier side of the internet, you need Linux. My son was devastated when they took down kicky-torrents, but it didn't bother me.
My favourite desktop is KDE. I tried many others, but I always am happiest with this. However, the reason I've tried all the others is that kde is totally euro, and regularly becomes unusable despite my massive efforts. This is written and maintained by union people who take long lunch breaks and take the whole summer off to go sailing. :)
The latest thing, was that kde refused to mount usb sticks after its latest upgrade. I followed this to alter the registry to make it work. blah
I did find a nice trick when making a new kernel for a laptop. You have to compile the kernel and on a laptop it takes forever. The trick is to do the usual 'make menuconfig' and then get out (or you face a zillion questions). Then do 'make localmodconfig' which eliminates the thousands of ticks for devices you never heard of. Then compile ten times faster, with a zippier computer at the end.