Windows XP Media Center Edition 2005. I tried Ubuntu Linux a few months ago but it was kinda hard to make it work; will come back to it once it has better support. Plus, I have seen Beryl on Linux and it looks pretty cool

I seriously have to question this comment. XP is indeed better than most of what MS churns out, and a damn sight better than Vista, which is appalling, but MORE STABLE than Linux? I seriously do not think this is the case, i have not had to restart my Linux server in two years, I would have to say that THAT is very stable. You're right about issues with new hardware, but then again you don't need new hardware to handle everything you need on a Linux based system.

I have Red Hat Enterprise Linux 5 server(dedicated, no dual boot) on that one and another server(my roommate's) running Windows NT2000, we both have 2nd and 3rd PCs running with XP, Yellow Dog Linux, and he has one with ME on it just to piss me off. I still haven't partitioned my PS3 HD to add Yelllow Dog to it, I'll probably just set it up on my external HD for it.

I guess I need to check out Ubuntu, the name is just too funny so i haven't messed with it yet.

Vista Ultimate, and I'm not particually fond of it.

Ah, but you've ignored the immediately following sentences:

You may be right about the OSes themselves, but when I start trying to use a variety of the software that's developed for Linux, I run into all sorts of problems.  This includes OpenOffice, and many of the programs you can rpm onto your system.  Linux does not seem to recover from program crashes very well.  And that applies to both Ubuntu and Red Hat (there are some Red Hat computers at work that I use), though I don't remember what version of Red Hat it is.  

XP Pro, because I work on Windows networks for a living so I need an XP machine. XP is great if you know how to keep it running, I've gone 5 years with no virus protection and no viruses, major crashes, etc. Almost never have to reboot like the old MS OS's. The average consumer, on the other hand... not so good at keeping XP running smoothly. It's unbelievable how many viruses some people get even with virus protection!

 Granted I have never had my own Linux server (we were just getting rid of them when I use to work IT) but the XP OS is incredibly stable.  The only times it has ever crashed on me was because of me using things like unfinished editors which is not in any ways XP's fault.  

Primary computer Mac OSX 10.4.10,
Because I've used so many different OSes and I Like the Mac OS by far the most.
It's very stable, has no viruses or spyware, its easily to work with, it works fast and efficient and it looks great. I can't ask for anything more in a OS. Apple makes Amazing products!

Gaming PC I dual boot Windows XP Media Center and Vista
Why... Well I have very few choices when it comes to computer gaming, If I want to play PC games I need Windows sadly and I installed Vista cause I got it for free and DirectX 10 only works in it. So what choice do I have? eventually I'll probily stop playing PC games and just wait for games to be ported to my Mac or stay with consoles.
Hooray that UT3 and StarCraft 2 are coming to the Mac!

All most forgot, My PC laptop runs Ubuntu. Best version of Linux todate. Easy to use (for Linux). I just needed something that ran on a 1Ghz Dell laptop that wasn't Windows. All I use it for is writing, listing to music, checking email and surfing the web

WinXP Pro! I tried Red Hat 9 & Slackware on my lappy but I they just didn't do it for me. I need to try Ubuntu, but for now the only Linux I use is Knoppix.

Yet the funny thing is outside of issues I run into with linux the only OS that has ever given me issues was OS X. Particularily when talking about Spotlight which I have had two major issues with and a third one that is related to one of the original two and the Dock.

Spotlight can eat resources sometimes which is problematic for me since I often have to have access to many files. The second issue with Spotlight was sort of fixed, for a while when you dragged and dropped a file from spotlight to the trash bin and than emptied the trash bin it would cause a kernel panic(aka grey screen of death). newer veriosn of OS X don't have this problem but all I can really do is just launch applications I can't drag and drop anymore which disables a key function or use for search features and I hope 10.5 fixes that.

On my Hackintosh I am not a big fan of the update features for Apples. In order to load OS X onto a dell I had to use specifically cut mach kernels that remove some of apples useless firmware checks for hardware amongst other things. The updates really screw with that and I usually check to see if I can get the new update first or if I need a hacked version but whenever you update it automatically turns on auto update. Which isn't a problem for my Mac Pro or Imac but a huge issue with my hackintosh(BTW the crashes I was referring to happen on real macs not this).

I live in SF I know many people who own macs there are plenty of macro viruses for a Mac and they are more of pain to remove than windows viruses. However having used both macs and PCs a long time I can say confidently only an idiot should be geting viruses for either system but people are idiots and so they do.

I am also not a fan of Macs because the OS is actually slower than XP even using Boot camp on a xeon based Mac Pro OS X runs noticeable slower than XP in almost every aspect except video encoding which is about the same.

 The Dock is a huge waste of space IMO while it is a feature many like to me it is annoying obstacle in trying to reach an information dense screen and many applications are built around the dock which makes it doubly annoying even though you can hide try running photoshp without the dock taking up half your screen(you can shrink it but it doesn't really help) and you will find yourself diping the mouse beneath the screen every time you won't to grab a picture from a file(photoshop dissappears into the dock when you click anything not photoshop.

However I do not hate macs. I do dislike the companies attitude(Pots shouldn't call kettles black:refering to the comercials) and the mac nuts overally simplistic and sometimes false opinons of windows. However some people like macs and others don't and that is fine as long as you realize your OS isnot perfect OS X and Windows ahve a long way to go.

Xubuntu, simple and works perfectly...    I don't like Gnome (from original Ubuntu). I like XP too, but in home I just use linux, those who think it is very hard should try a bit more... the only problem is with ATI and some wireless cards, I realy hope that AMD do somethink for linux users...

EDIT: Oh yeah, the reason I like XP and love linux is stability... winXP is the better windows ever and like everybody uses, is easy to find suport. Xubuntu is a bit more dificult to find plp using, but I never have to do nothing to make it work (or install anti-malwares, or thinks like that), I just use more advanced thinks in linux to try new programs (like Compiz-Fusion).

btw: http://www.ubuntuvideo.com/ubuntu_gutsy_7_10_with_compiz_fusion - just remember, it is a bit unstable yet...

About stability, someone says here that XP is more stable, it is not, it very stable if well upgraded and virus-free, enough to a home user, but is not nearly stable as a Debian server system, I work with TI and is impossible to keep a windows system more than a week running, and we have some "unbrokeable" linux system that works without restart for more than a year... so ok to say that windows is suficiently stable, but not more than linux...