Small HTPC, not underpowered?

I'm looking to build a small HTPC to watch downloaded or streamed content, running XBMC. I'm looking for a balance here between small, quiet, and adequate power for an HTPC. I'm a long-time builder, but I'm hoping I can avoid wasting time and money on parts that won't meet my needs, so I thought I'd reach out to the community.   I've gone pretty detailed here, but I'm flexible if someone sees another way to meet my goals.

First off, I'd like to mount it to the back of the TV via VESA. My router is in another room, so it will need wifi, ideally onboard. I'd love this to be quiet, if not silent, but not run too hot. Other than that, I don't need much more than an HDMI hookup and the ability to play any number of codecs at 1080p without dropping frames.

I've been researching for a few weeks now, and there's some interesting stuff out there. The Raspberry Pi, Atom chips, and the new NUC options all look promising, but run the risk of being underpowered or lacking features. So here's what I'm thinking for a build:

Mini-ITX board: Ivy bridge sounds like a good option for it's low power, keeping heat and noise down. Willing to go with a premounted CPU, but so far nothing I've found has onboard wifi, HDMI, and can output 1080p reliably.
Celeron CPU: Good low-power option. I'm assuming I can use the onboard graphics processor for my needs, but if this chip is underpowered, can go bigger. I don't need a gaming rig though.
Case: The Antec ISK 110 looks great, and a likely purchase, though I'm open to other VESA-mounted options.
Cooling: Passive would be ideal, as I'd love to make this silent. However it could run hot, which I want to avoid.
Hard disk: I've got a spare 128gig SSD for this build.
Controlling the box: I own a Dinovo Mini, so I'll be using that or the XBMC Android/iPhone apps.

So I know this is a challenge, which is why I'd through this out there to see what you guys think. Component suggestions? Any pitfalls to watch out for?

Thanks in advance!