For Linux, I'm a big fan of Debian-based distros. I have used Ubuntu as my desktop for years, but recently had trouble with 8.04 on my laptop. I switched to Linux Mint which is basically Ubuntu with a few extra packages, codecs and themes. It works much better with my laptop , but I may give the new 8.10 Ubuntu distro a try just to compare.
I used SuSe for years as it was always my favorite RPM based distro, I'm not quite as crazy for OpenSuSe but I can't exactly say why. They are still on a flaky version of KDE 4 (IMHO) and the install of 11 took forever vs an Ubuntu install (2 hours VS 15 minutes).
For servers I have a mix of Ununtu 8.04 LTS server, FreeBSD (fav for servers) and Apple Leopard Server (quickly becoming new favorite). My firewall is PfSense which is based on MonoWall and FreeBSD. My main HA server is HouseBot that runs on a PIII 833 with 256MB of ram and WinXP SP2. It is solid as a rock and runs until it loses power or I have to restart for other reasons (moving, power failure, etc.) but I also ONLY run HB on it and leave ancillary tasks to other boxes. My wife runs Apple Leopard on a MacBook, my daughter has Vista on a laptop and XP on her desktop, I use Linux as mentioned above, and trimmed down versions of XP or Wine on linux to run the HouseBot client on the touchscreens.
And yes; Jobs is a Jackass, but man I love his products. I also agree that we've yet to see anything better than OS/2 Warp.
Terry