Comment Windows 7 and Media Browser (Score 4, Informative) 536
In years past I've used XBMC on the Xbox and Linux, then more recently Boxee and MediaPortal. I started wanting something that just worked, and was a bit easier to setup. I really like many of the Linux media programs, but they do take a bit of maintenance. So when the RC of Windows 7 came out I figured I'd give it a go. Once I found Media Browser (www.mediabrowser.tv), I was sold.
So reasons I think Windows 7 is the way to go.
1. Media Browser - Fantastic plug-in for media center. Almost as good as XMBC in it's prettiness and useability. Very impressive to show off to your friends and high Wife Acceptance Factor.
2. Easy - It took me about a week of fiddling after work to get it setup the way I wanted.. and I had no issues getting DTS HD or pass-through audio to work. Very easy to get hardware accelerated video to work with ATI. If you use windows 7, check out the antipack, gets your hardware accelerated video working fast, along with all your audio. (http://babgvant.com/blogs/andyvt/archive/2009/08/02/antipack-get-your-videos-working-without-destroying-your-pc.aspx)
3. Cheap Video card - I bought a Radeon 4350 off of Newegg, with passive cooling. Does 1080p video with 1 - 5% cpu usage.
4. NetFlix , Media Center has a NetFlix plugin, no HD video, yet.
5. Easy TV - Has a nice TV Guide, easy to make it work right. I do not have a cable card tuner for it yet, but Ati has on you can get off of ebay, and new models are coming out next year. Cable card tuner would eliminate your ir blaster issue. In the mean time there are a few MS Media Center remotes that come with ir blasters. Also TV shows go right into Media Browser.
As this is slashdot I bet I will get spammed for saying so, but IMHO it is the best all around system out there right now.