I like them both. Playing Bethesda RPGs, always PC (mods. yes.....mods...). For classic games and flight sims, obviously PC.
I like keyboard/mouse - but I also like controllers ergonomically, you can sit back and not be hunched up over a keyboard with another hand off on a mouse, and analog walking has it's advantages in terms of variable speed and diagonal movement that WASD can't match. There may be controllers out there that can do that but I haven't looked in a while.
For games with the family or friends, or for relaxing in the evening, it's a no brainer, nothing can beat sitting down in front of a large TV on a couch with 7.1 surround and a 4K HDR panel on the One X. It's phenomenal. Gears 4 is something that has to be seen on the One X with a good display. If you are so inclined you can of course move a PC or have one for hooking up to your home theater, but everything just works easily with a One X that is designed for being in a living room, from the interface scale to the sound/video configurations.
The flip side of the closed/pay for argument that PC gamers like to make as a negative is parity, reliability, security, and features. I'm happy to pay for XBL. It's not that much per year in the grand scheme of this hobby, it has excellent party and matchmaking with seamless voice chat. Sure it occasionally has hiccups but so do PC services. And you get 4 free games a month. Everyone on there is playing on a more level playing field with similar controllers and hardware platforms (although some deviation with Elite controllers and the One X), the guy who spent 2k on a high end gaming rig and 8 billion DPI mice won't have as much of an advantage just because he had a huge bankroll. Oh and cheating is much harder. Cheaters ruin PC gaming constantly.
Overall...for me, I like them both. I try to keep a moderately functional PC that while not a huge insane beast can play modern and older titles well, and I also really enjoy console gaming at times too, and for that my choice is Xbox (although yes MS could really up their game on exclusives...)