Maximum PC

Hi, I am new to this site and I came here hoping i could get some help.
I am currently in the market for a Desktop PC and I sadly do not know a lot about computers. The reading I have done has made me narrow down a few specs for my computer however I would love to know if I am correct that these are what I will want for my computer or is it going to be obsolete in a year or two with these. I will be playing video games such as Diablo 3, Starcraft 2(and expansions), and League of Legends on this computer so I would love for this machine to be able to run them on high graphic settings. I also do some work at home with microsoft office.

I want an:
Intel Core i5-2500K processor
ATI/AMD Radeon HD 6950 Video Card
1TB or larger hard drive
8GB or more of RAM

If these would be good choices great, if not what would other people recommend instead?
I would also love to know what kind of monitor to get with a system like this?
What else should I be putting into my computer specs that would compliment these items?
Where is the best website to customize my computer build and then purchase(if this is possible)?
What would the price range roughly be for this desktop computer(I am hoping to be under $2000 CAD)?

Thank you in advance for any help that anyone is able to give me to any of my questions.