Emulation HTPC Build help

Hi All,

I'm in the process of getting a parts list together for my first HTPC build. My first build at all actually!
I'm stuck working out what I'll need, as there are tons of forums and guides, but none which address my requirements that i have found.

Here's what I need it to do:
- Be quiet. Will be in the living room in home theater setup. Therefore, should also be a nice looking case.
- Play emulator games. PS2, Gamecube, Dreamcast and below. Note, i don't intend to play any modern PC games - I hear Hyperspin may be the way to go with this...
- Run all media i throw at it - ie. 1080p movies, Blu-Ray playback (optional), all my music etc. through XBMC.
- Be quick. Just want to hit the on button, load quickly into XBMC from startup, and configure my iPhone/other remote to have control from there

From the research i've done, i've put together the following as a list of what i might need.
- Case: Silverstone GD05 Black HTPC Case with USB 3.0
- CPU: Intel Core i5 3570K LGA1155 ------ Would something like i3 3220 suffice?
- MBO: ASUS P8B75-M-LX Motherboard
- RAM: G.Skill Ares F3-1600C9D-8GAO 8GB (2x4GB) DDR3 ------- Would 4GB Suffice?
- PSU: Thermaltake Litepower 500W Black Edition
- SSD: Samsung 840 Series 120GB SSD Retail Box
- HDD: Western Digital WD Green 3TB WD30EZRX
- Optical: LG CH12LS28 Blu-Ray DVD Combo Drive ----- Optional. Dont use blu-ray now. Just thinking ahead.
- GPU: Gigabyte GeForce GTX660 Ti WF2 2GB ---- Necessary??? Not sure...

So here's what i need to know:
- Will all this stuff fit in the case?
- Will it all be compatible?
- Do i need it all to run what i'm planning to?
- Is there anything i'm missing?

I will be running Windows 7 64-bit, as i hear it's best for emulators, and was hoping to use my existing PS3 controller, but will look into getting a XBOX 360 wireless one if it's easier for key mapping.

I have seen a lot of simpler systems in lifehacker articles and whirlpool forums that suggest i may not need this level of specs, but from what i hear, PS2 and Gamecube emulation is quite CPU intensive.
If it's going overboard, please let me know too!!!

Any advice you guys can offer will be hugely appreciated, as i've been going back and forth over this for a few weeks now and am ready to get moving!

Thanks in advance!