Originally Posted by Zer0CoolX
anytime i have someone ask about HTPC, i ask why? Whats your goal with it?
Do you have another computer thats capable of playing LoL? If so is it relatively close to the TV?
The reason i ask is, putting the gaming aside for now, an HTPC doesnt really offer a whole lot over a much cheaper streaming device for internet based content like netflix or streaming your own media. The one caveat being recording live TV if you plan on doing that. If gaming on the TV is what you primarily want, then it may still be beneficial to get a streaming device for things like netflix and playing your video files. If you have another computer close enough to the TV you may be able to just run the display cable to the tv and play that way. For playing local media or streaming a dedicated device like roku, google tv or apple tv will be way more energy efficient and focused on that purpose.
A good example is my PS4 can do netflix and amazon streaming etc...and i almost never use it for that because my Vizio Co-Star can do it just as well, but came with a nice remote and uses way less electric.
An alternative approach may even be what i just did, i built a server. This serves my media to all my devices (co-star,nexus 5, samsung s4, kindle fire HD, desktop gaming rig) and i can also view the content via any browser even outside my network. I can goto a friends house and connet my phone hdmi and play any movie on my server, or open a browser from any internet connected computer to pull it up. The server is also a file server, backups my gaming computer, and can run downloads and stuff without needing to run my power hungry gaming rig.
I use Plex Media Server and its awesome. I personally dont like XMBC although it may have gotten easier to setup now. Plex has apps for devices or can be watched via browser. It automatically grabs posters/art, metadata, etc and organizes the content very nicely.
My server is in my sig if your interested and i have a build log for it.
To answer some of your questions, if you want BD playback go with Windows. It will give you more options and easier to get working. A card like the 750 or 750Ti would be a good choice, depends on your budget and if you may want to play other games in the future.