Well welcome to PureOC. We are glad you stopped by to ask your many questions. Let me try my best to help.
Ok first thing. Custom water cooling shouldn't be an option at this point for that setup. You will gain very little from that investment since you cant OC much and you dont have a GPU worth getting a GPU block for.
based on what you are saying I would go with an All in One Cooler like the H100i, kraken X60, X40, TT Water 3.0 pro, The new ones from Antec. Check out some of our reviews on coolers and pick one. Get either a 120mm with 2 fans or a 240mm rad.
Case changes are easy. Go with whatever you like. Think about what you might what to do with it in the future and pick a case that supports those ideas. Nothing worse then buying another case 3 months later.
Very important!!! If you are planning on running F@H 24/7 you MUST invest in a PSU that can handle that continuous stress. So EL'Cheapo PSU will cost you dearly in the furture. YOu dont have to go top of the line but it cant be cheap and it must be rated higher then your actually power draw. I milked a PSU like you are talking about and it cost me my entire system. It is also the reason I found PureOC. Weird how things work! If I were you I would go with at least a 700-750w PSU Bronze or Gold rated made by one of the more known names in the industry. Antec, Corsair, Cooler master, Thermaltake, Seasonic ect ect. It should not cost you too much.
Not sure if I missed anything or not. But its a start. Again Welcome to PureOC!