Help me decide on an OS for My Home Theater PC

Just use the OS you already have.

XP Pro is good enough. I've heard MCE streamlines it but I've never had it.

Unless you specifically have a lot of 64-bit software, I don't see a reason to go with 64-bit. I used XP Media Centre on my previous laptop, with a USB tuner, and I now use Vista Home Premium on my self-built HTPC. Tailor it towards the main use (i.e. more ram and faster, larger HDD's for TV recording, bigger and better GPU's for games, and faster CPU for media encoding). A balanced set like you have will allow you to do most anything, but not excel at one specific thing (my system is the same).

For today's HTPC, I'd recommend Vista Home Premium, 4GB ram, dual 500GB 7.2k drives, and single or dual 9800's / 4850's. Any "core" series CPU is also more than capable for the typical tasks.

The other big question is software. If you are familiar with linux, then that can be a great option for HTPC use (mythtv, etc), because it is relatively efficient, but Windows is still where it's at when it comes to drivers.

For the true HTPC experience, get a remote and/or wireless keyboard. With my PC in sleep and a Harmony 880, the system can start in under 10 seconds, for that "instant-on" feel of consumer electronics.

The only thing I don't use my PC for at the moment is watching and recording TV (even though I have a couple tuners here, including an OTA HDTV stick).

So, the biggest challenge will be getting all the software to co-mingle nicely.

...if that long-winded post helped you at all LOL

Media not gaming. I am running a AMD 4850e and ATi 3200HD. No problems at all including HD video.

The question to ask yourself is whether Vista (or XP MCE) is worth the $ for the built-in media functions, or whether you want to try and get the same experience with 3rd-party software and your XP Pro.

If you have all the pieces already, then there is no reason not to try and set up a HTPC with what you have, and if it doesn't work out, then look to upgrade the software or hardware.

You may want to read some forums on your tuner to see which OS supports it the best (Vista may be able to handle HD cards better than MCE, for example).

Maybe an option to look at is the Antec Fusion Max. It's a great HTPC case and comes with the LCD, Remote and software, so would work well with your XP Pro. You may also be able to buy the LCD/Remote/Software as a package by itself to use with your own case.

Just throwing out options. It's all up to you

Other. Vista

Vista is like XP MCE; it has Media Centre built-in (as long as you get the Home Premium or Ultimate version). It is practically the same Media Centre as XP MCE, just refined a little, with better support for HDTV, I think. As I say, I don't use my HTPC for TV, but from what I've heard, some people prefer the Media Centre in Vista to MCE, and some vice versa. I have tried a couple of other programs when I had XP MCE, but just found the integration of Media Centre to be the best, and remotes designed for MCE work right out of the box (as I say, even a Harmony 880). I haven't used an air mouse, but it may be a good solution; my Harmony doesn't control mouse movement, just media functions.

As for recommendations for XP Pro, all I can say is download a demo of various media programs to see which you like best; they all perform slightly different.

The only difference between 64 and 32 bit is the drivers and whether the programs you use will take advantage of 64-bit. It may be harder to find 64 bit drivers for all your hardware. It would be nice to have 64 bit to use 8GB ram, but I barely make use of the 4GB that I have now.

As for Vista vs XP MCE, the one is $20 cheaper and newer (i.e. supports newer features), while the other is more expensive, but has more support because it is older. FYI, I don't think XP MCE is even available in 64-bit.

There may be a compatibility check on the MS site to test your system, otherwise check the manufacturers pages for all your hardware to see if they provide 64-bit drivers. 32-bit drivers might even work, but no gurantee. Can't help much there, as I have no experience with 64-bit.

I've used Windows Media Center before both the XP and the Vista versions. It works quite well, but I happen to prefer Beyond TV from snapstream media. The one advantage you gain with Media Center is that if you have an XBox 360 your 360 can stream all the media center content from your PC over your network (Including recorded TV). Not bad considering it comes as a part of Vista Home Premium and Vista Ultimate. In fact, I'd say it'd be worth it just for that.

Vista 64bit has MUCH better support than 64bit XP Pro ever got. So you should be relatively safe putting 64bit Vista on the system. Unfortunately Microsoft never made a 64bit version of XP Media Center Edition.

Vista Home Premium SP1 64bit is running on my new pc that's for HTPC, gaming, video processing, watching TV, major web browsing, and video editing.

http://www.notebookforums.com/thread223665.html

Media Center can't pick up the signal from my pci tv car; my Kworld TV software can't use epg data for recording setups, Magix Movies on TV and DVD records well but doesn't stop and restart recording to avoid commercials while watching and recording TV. - You have to record straight then edit out commercials later. But this software is good for combining several quicktime videos recorded on my Casio Exlim ZX80 camera for youtube.