On my day-to-day workstation I run XP; I’m tethered to it both by long familiarity and by some engineering applications that simply aren’t available for Linux.
But... I also run Ubuntu (currently Edgy) in VMWare on my XP machine. I love it! I found that Ubuntu is the best distro for my needs, after dinking around with Fedora and Slackware. Simple to download and install, easy to upgrade, easy to install new apps, intuitive to use. I am also impressed at well the Ubuntu workstation interoperates with the rest of my (primarily Windows) network.
I have lots of memory on my workstation so I give the Ubuntu VM a gig and away it goes. Performance is quite satisfactory for me, even at tasks like compiling a uCLinux kernel. I highly recommend the VMWare strategy for anyone who is currently running XP and wants to explore Ubuntu. (Incidentally, one of the reasons I selected Ubuntu is that it’s one of the free distros that is officially supported by VMWare.)
I also use Ubuntu (in this case, Dapper server) as the OS for our corporate intranet server. The Ubuntu server runs, in turn, on a Xen-based VPS. We are a small, geographically-distributed corporation, and this scheme has worked out very well for us. I found that administering Ubuntu server over a TTY interface presents a significant learning curve to a Linux N3WBI3 (heh), but not unmanageable, and there’s lots of help on the Web if you’re willing to look for it.
Conclusion: Linux and Ubuntu get 2 thumbs up from me!
Give it some time and you don't know how you lived without it. Incidentally I heard the next incarnation of windows server will have by default *no telnet (yay)* *Will run sshd (yay)* and will include TUI tools for remote administration (yay).