Thanks for the information. My sister's ordered the microserver and she wants me to setup a media PC for her. I was going to go with the ATI, but thanks to you, I'll be able to save myself some grief by getting the Nvidia card instead.
Glad I could help.
Remember the 5450 / 6450 is still preferable if you're going to run Windows, since it uses less power than the 25w the PCI-E slot supplies.
The GT210 is old and IMO outdated, and uses 29w, but should work in Linux, but I'm going to get a GT520 for a second PC. I've been looking around and the guys from Rebeltech mailed me back saying that the Gigabyte one on their site as a LP Bracket included, even though the Gigabyte website states the LP bracket as an optional extra.
So it's only when running XBMC Live (or Openelec) or XBMC-with-Linux as OS that you'll have a problem with the ATi cards. (And also only with 1080p content)
jannievanzyl said his Linux and XBMX system is working perfectly with his GT520, that's why I'm looking to get my hands on one as well.
If anybody manages to get the ATi cards working in Linux (/XBMC Live / Openelec) on the N36L with VAAPI enabled and 1080p (10GB+) files playing perfectly, please reply to this thread, there's really a couple of guys looking to get their hands on this valuable info!