What do you mean setting up the OS so its suited for your TV?
a variety of things that take time to set up properly. For example, when my PC boots (I'm running windows 8 on my Steam Box in the living room) it creates an ad-hoc wireless network from the dual wifi on the motherboard, that I use for things like remote display on my phone. I try to make windows as invisible as possible (black background, auto-hide the task bar, etc) and boot into big picture mode immediately.
I control my entire PC using a Gyration MCE remote. I need to spend some time with EventGhost to reprogram a lot of the keys on it for specific applications, like XBMC - i have a button on the remote that automatically queues and item, and so forth.
I write a bunch of scripts and then turn them into executables and put them into Steam as non-steam Apps, then create icons for them. Like, take for example The Longhorn Network (I'm a UT alumnus). I don't actually have u-verse TV, only u-verse internet, but that still lets me log in to the longhorn network streaming website to watch the channel online. I created a firefox profile such that, when I launch into that profile, it goes full screen, sets my homepage to the longhorn network, automatically logs me in, etc. I created a batch file to launch firefox within that profile, then turned that script into an executable, then put the executable into Steam, then gave it an icon, and now when I select that icon from BPM, it launches into The Longhorn Network at the press of a button.
Lots of little things like that, that most people don't consider. I also have to set up my Xbox controller dongle etc etc. All this stuff is things you only have to do once, but they still take time to set up. I usually devote a weekend after building a PC to doing all these hundreds of small things I do to make the experience as smooth and seamless as possible.
EDIT: Once I get my environment configured just the way I like it after a clean install, I also mirror my harddrive so that, if I ever need to return to that point, I can just restore from the mirror. I also frequently mirror my current configuration onto a D-Link DNS-323 server in my house in a Raid-1 configuration with a script that boots me into offline mode. That way, should anything ever happen to steam, I can restore from an offline point and have unlimited access to my games, even if I have to "reinstall."
Setting all this stuff up to be automated takes a while, too.