Without a GPU your power requirements will be minimal. For an HTPC that I wanted to be quiet I would go for a lower power CPU like the i3 2120, the G630 or the G870. If you're not gaming, then the processing power that you need is minimal. The Seasonic SS-300ET is a nice little PSU that will be more than enough for any HTPC, but I can't make that recommendation until I know the PSU form factor required for your case.
The case is a fractal design define mini. While it is unecessary for the type of build im doing I wanted to get a cpu that I can overclock in the future. I was going to go with a 2500k but for the extra $30 i could get improved graphics from a 3570k since I wont need a gpu.
If you're going to be doing any gaming, then it would be better to get one of the lower end CPUs that I recommended and a low-end GPU. A G630 with an HD 6770 will cost less and get better gaming performance. If you're not gaming, then the 'better' integrated graphics won't do anything for you. If you're going for quiet and this is going to be used as an HTPC and not for gaming, then you don't need the better integrated graphics and would be better off going for a lower power CPU.
The Define Mini will accept ATX PSUs with a max depth of 170mm when using the bottom 120mm fan (200-220mm without that fan installed). The SS-300ET is only 150mm and will fit in your case.
G630 or i3 2xxx... I mean Im not on a budget where the cheapest option that i can get by with is the best...considering i was content with the price of 3570k..i am fine with spending more if needed and was better option