Yea it's not like building a car engine or anything. You can't put things in the wrong place really unless you're just that ignorant.
You can chose any case you want, long as it fits the motherboard and setup you want to install. I usually chose the Corsair 200r or 300r as a good quality budget build case but not everybody likes them. On that note, I wouldn't really change too much except maybe the motherboard, even though what I have listed is fine. I know that's what I linked the other guy, but it fits perfectly with what you want and your budget so why not. Also on the parts, as I state in my thread stickied atop this sub-forum, spend more money on the parts that give you the actual FPS, not the bling. In your case, the budget is high enough to warrant maybe spending extra on the case but personally I wouldn't. I had 2400 bucks worth of rig in a 75 dollar case before lol.
As for monitors and peripherals. Honestly, I wouldn't spend too much into a keyboard, but a mouse can be a huge game changer for some people while gaming. I personally use a Razer Lycosa which to me is a typical run of the mill backlit keyboard, but made sure I got exactly what I wanted in a mouse which is the G700. The mouse is as personal preference as headphones and other such things. I highly suggest going to a Best Buy, Fry's, Microcenter, or whatever you have for a "tech" place to get hands on with some mice to decide what you like the best.
Monitor, that's up to you. Some people like small, others like big, myself I think 24" is perfect. My only thing is, smaller sizes like 21-24, 1080p, 27"+ better be a higher resolution for the best pixel ratio. Stick to brands like Samsung, Asus, Dell, or NEC.
