You don't need 700W for just the parts you listed, a 350W-400W psu is more than enough, if you have a gfx card, then you might bump the psu for a 500-600W.
Get the i5-3570k, it has the intel hd 4000 graphics(i'm guessing that you'll run in integrated graphics) and if you want to overclock, this is the cpu to get.
I rather get the asrock z77 extreme 4, overall, it's a better motherboard.
First of all, the Z77 chipset motherboard will serve your LGA 1155 socket, i5 3570 CPU very well. So that is compatible.
8GB of RAM is a good amount for any sort of computing, whether it be gaming or just home office. Also it is Corsair Vengance RAM, so you are guaranteed quality.
An SSD is always a good option to have and the fact that it is 120GB is all the better. I would recommend putting you Operating System on this and use your HDD for larger files like games and movies. Yet again Kingston is a good brand (I have their RAM, excellent)
A 2TB hard drive will be more than enough for 'casual gaming' and movies. Seagate is a leading HD brand aswell.
You have a very powerful PSU from a good brand, OCZ,however it is a little overkill (too much for what you need) for your setup. It won't do any damage and there will be plenty of room for upgrades, but I'd maybe switch down to 600W and save some money for other parts. Which brings me onto my next point.
Are you getting a Graphics card? I would strongly reccomend that you do. Even for causal gaming the HD 2500 in your i5 CPU won't survive today high end games. I'd just get a cheaper on, like a HD 7770.
So yeah, apart from the slightly over powerful PSU and the lack of a Graphics card, it all looks very 'appropriate' to me
*Sorry I was a little late here and have repeated things because I didn't see the other replies when typing this...
more specific...Dual Monitor Nvidia Gforce 8600 Gt Graphics card
You might just get the i5-3570k, the intel hd 4000 should be as good as a 8600 gt with lower power consumption, most boards also supports dual monitors.
And get a quality psu within 400-450W.
For casual gaming, it might do, depends on the games, if not, you might want a better card like the 7770 or 650 ti.
Change the motherboard for the asrock z77, if you don't plan to overclock, get the i5-3350p or i5-3470 and the asrock z75 motherboard or any other h77 motherboard.
Just get the asus LK with the free ram and you'll probably won't need to sacrifice anything.
It's a good motherboard, you'll probably won't need the features of the asrock.
But if you have already an external hdd and other hdd, you'll probably won't need the 2TB hdd, just get 1TB or 500GB, if you don't need much space.