I've mostly used Ubuntu 8.04 LTS - here are a few of the problems, all on hardware carefully chosen for reliability (Gigabyte ultra durable etc) and Linux compatibility:
- Ubuntu server - kernel panic due to WiFi driver, had to install kernel from 8.10 - this on a WiFi card chosen for compatibility
- Ubuntu desktop with 11.04 LTS
- frequent hangs/freezes for another reason - only solved by switching to Linux Mint 11 (Intel G33 GPU)
- Ubuntu desktop (main PC), NVidia 7900 then GTX260:
- frequent hangs/freezes over some months - solved by irqpoll and all_ide_generic on kernel command line
1. Flash full screen - I can go full screen but it takes over the screen then stops, and I can't recover normal desktop without ssh-ing in from another PC to kill the X session. So I reboot.
2. Firefox frequent hangs - goes to 100% CPU on one core a lot at the moment, perhaps due to a single tab but it's hard to find which one. Currently disabling extensions.
3. Firefox bug where IFRAME popped out into a new window with corrupted display. Now solved but went on for a long time.
This isn't remotely all the problems, just perhaps the 10% that were most serious. Lots of other problems with sound have caused problems, and my Dell 3115cn printer still won't print with correct size from some applications.
It's not just one PC, nor just one distro version, though it has all been Ubuntu. Since Ubuntu is the most popular Linux distro it's reasonable to assume it should work OK, and most of these versions were LTS which is supposed to be stable - I usually wait 6 months after LTS for key bugs to be fixed.
Meanwhile, Windows 7 is really quite stable - it has some problems on my laptop PC with lots of corporate overhead, but on two other PCs it works rather well. These two are almost never rebooted. I also multi-boot into Windows XP for gaming, which is quite problem free. I do have many more minor application-level problems with the Windows systems, but that's partly due to who's using them (less techie person) or what they are doing (HTPC).
Linux takes a lot less maintenance once it's working correctly (easy apt-get type updates, no need to reboot, no antivirus overhead), but Windows in my experience is much easier to get working with all hardware functioning correctly, working full screen Flash, etc.
I am quite geeky e.g. building own kernel occasionally, getting a small fix into Apache 2.0, writing wiki code, etc.