If you live near a Microcenter you can get a i5-4670k plus a z87 motherboard for what a plain 4670 and a h85 motherboard would cost you. Since Microcenter sells the motherboard CPU combos much cheaper then newegg. Also while you are in Microcenter you can have a hands on look at cases...at least it might give you a general idea what you want.
I say this because a 4670k will let you overclock...not that it is needed for a HTPC but if the price is a few dollars difference having a 4670k will give you the option of running it at a higher clockspeed, IGP included. Also down the road if you need it you could add a nice dedicated GPU that would be way better then Intel's IGP. I Also suggest a nice CPU cooler like a 25-30$ Coolermaster Hyper 212 EVO over Intel's crap cooler that will probably be noisy as heck and does not cool well at all. Also Intel chips run hotter while using their IGP along with the CPU cores. I know this was the case with my i7-2600k and My i3-2125. My 2600k is no slouch but running with all 8 threads at 3500mhz on my H67 motherboard in my one HTPC SVP at 1080p cranked all the way up can bring it to its knees using 100% CPU power and this is with a dedicated card a AMD HD7750...now that same rig had its i3 -2125 back in it where it belongs and with artifacts masking turned up to the maxin SVP and madvr chroma and image upscaling set to jinc with 3 taps my cpu is running at 45-60% usage along with my 7750 at 75% usage that will drop to 50% if I overclock it from 800 core to 1125 and 1125 mem to 1350. That is because I was gaming last night and noticed my video card was overclocked when i was testing SVP while writing this post and as soon as i reset the GPU to stock settings the 49-50% went up to 75% usage. Now my 2600k in its proper home a p67 gigabyte UD4 running at 4705mhz is still busting 60% and higher cpu usage with SVP setting turned up....but not totally maxed a couple setting are 1 click from max.
Also MKV's AVI's ETC. run at 23.97fps to 25fps with rare cases some will be at 60 fps, but a 60 fps MKV is very rare. Another reason I am recommending you go with a overclockable CPU is because of The Smooth Video Project that takes all your MKV's AVI's and makes then run at your monitors refresh rate...and let me tell you a 60fps movie is so so much smother then watching one at 24fps. But it can use tons of CPU power and the SVP package comes with MPHC as the player along with MADvr, FDDshow, AVsynth ETC all to improve the picture quality. I prefer to watch a 17gb MKV of avatar @ 60fps with the picture enhancement with SVP, MADvr etc, over watching the Blu Ray disc in a stand alone player. Yes the picture is that much better that I will convert a new Blu Ray disc to a MKV file to watch it using the Smooth Video Project @ 60fps and video quality enhancements the picture looks much more realistic and fluid. Much better looking then my stand alone 3D Blu Ray player
Also The SVP Has adjustable Ambilight technology for the black bars on the top and bottom of the screen that is very adaptive to whatever color is near the edge of the black bars. I have mine set to level 2 and it looks great making use of the whole screen but is not too aggressive that it over powers the movie...it just make the rest of the screen look like it should be there. It works on 4x3 movies/tv shows as well colorizing the black bars on the right and left sides of the picture to whatever color is next to the black bars doing a great job blending them in to the point they add to the movie experience.
Here is the link to The Smooth Video Project. There is a youtube link showing the Ambilight tech in action right on the front page. http://www.svp-team.com/
You can also read the forums if you want a idea on how Intels IGP works with it and probably more info on the CPU power it can use along with wether you want to add a dedicated Video card down the road considering my 3 HTPC's use dedicated cards and with my setting used in Madvr on my 7750 I can use over 75% of the GPU's power watching a video. My 2600k and SLI 560tis will use over 55% on the main card and 15-25% on the secondary/slave card. I have used it with the onboard HD3000 IGP on my 2600k and my i3 2125 that also has the hd3000 IGP and it worked but it works and looks better with a dedicated card. Like I said read the SVP forums for more info or PM me if you/anyone have any questions. but one thing is for sure a 60fps+ video looks a heck of a lot better then 24fps....24fps looks choppy now that I am spoiled ith 60fps.
Here is a little snippet from the frequently asked questions.
Which CPU is better for SVP?
It depends but the faster is the better.
The performance depends almost linearly on video frame size: 1080p FullHD frame is 4 times larger than 720p and 720p is 4 times larger than DVD. Note that proper video card could improve performance significantly but for high quality 1080p interpolation you still need powerful CPU and having 4 cores at 3 GHz is a good start.
Which video card is better?
The shortest answer is: any modern low-mid-level video card (at approx. $70-125 price level) should be good enough for all video related task (video decoding, frame interpolation and post-processing) at the same time. But don't forget about raw CPU power.
See more detailed answer on GPU Compatibility page.
Like I said If anyone has any questions at all you can PM me and I can walk you through proper setup and tweaking. Over the phone if need be, As long as you speak English.