I have made a gaming computer from scratch recently. By looking at your specs i have read, i can happily say that what u have there is a very good gaming computer. Here are my ideas and suggestions.
Processor: your processor is great although it cannot be overclocked. It is Ivy Bridge compatable which means it unlocks some features such as Gen3 PCIe 3.0 16x ports. i5 supports Hyperthreading but when you go for a i7 3770 it has way too many features which just beats i5 no matter what ppl say. besides i7 has more multitasking and sounds better to tell ppl than i5 dont you think. So yea u got a great processor dont change it and dont go for 2011 pin LGA CPU as you will need a new Mother Board and you will get ripped off with sandy bridges that dont support PCIe 3.0 gen3 yet and when they come out, they will prolly cost like 800$. trust me the LGA 1155 vs 2011 LGA is very little difference but in price it is a major difference.
Motherboard: Judging by your Motherboards multiple features, i will say that its a great decision if your a radeon AMD fan. I'll explain why soon. From what ive also discovered, your motherboard PCIe slots arent too bad. The 3.0 x16 port is great for 1 GPU card. If your looking for SLI/Crossfire then i must tell you that the 2 GPU cards will have to be Radeon indentical GPU cards. Nvidia SLI isnt supported in this MotherBoard but crossfire AMD is so if u do wish to have 2 Radeon GPUs then yes you may have Dual GPU support.
Graphic Card: As ive stated previously you will not be able to use Nvidia GPUs in SLI (ive referenced a link explaining more about Crossfire). But anyways enough about that. the GTX 660 GPU is great. Its a magnificent card. The only thing that bumped me off about it is that for 50$ more you can go from 192-bit to 256-bit with 670 GTX. This means more bandwith = more performance FPS but im not saying the 660 isnt badass as it is still a beast of performance. Note: the 660 GTX isnt Over Clockable but the GTX 660 ti is.
Memory: 8gb ram is great at uDIMM 1333MHz. It will play games of today. HD modded games maybe not too well (Dont quote me on this). For more graphical games id suggest 16GB of Corsair Vengeance ram. 32GB is a waste because my machiene doesnt reach no where near it as mine has 32GB aswell. 8GB ram with Multitasking applications will handle well upto a certain point as do many rams depending on the GB.
Note: 1800MHz is needed for Overclocking.
Power Supply PSU: the Watts of the PSU should be able to handle your set up. Make sure your PSU is Micro compatable uATX and has the output cords for your periphirels and hardware.
Cooling: yes you need a cooling that supports 1155pin LGA slot but you havent given a type of cooling device. might i suggest that for what u will be doing, the Cooler Master Hyper 212 Evo should do you finely, its a 4 pin Cooling fan which matches your Mother Moard and CPU nicely.
Sound: the 5.1 from the Rear I/O should be fine for what u need. You can configure your 5.1 setup in Realtek Audio Software. your Mother Board supports 8.0 from Realteck onboard so dont go wasting money on sound when that should do all you need.
Case: make sure its a uATX Case that will support your DVD drive Bay, HDD bay, PSU input and most especially your Mother Board uATX. so Micro all the way :)
In summary, for a hard core gamer i am. I would say you machiene is fairly sweet and will play Max Payne at 40-60 FPS on ultra (dont quote me on this). so hey its pretty good and dont be discouraged. Also for Hard Drive id suggest a 2.5" SSD for ultimate speeds and rendering which will boost your games dramaticly. I brought a 120GB SSD for 100$ whcih has been so great. For example: Minecraft is not even a secon and its all rendered with a 512x512 Texture pack and all. 100+FPS. So i suggest looking around where you live and also make sure your case has a 2.5" drive bay. If it doesnt then id suggest buying a 2.5" Mount Bracket to make it fit a 3.5 drive bay"
I hope ive helped and enjoy your Gaming machine. Go get em!