I'd recommend you over specify on certain long-term components, like the PSU where redundancy comes second to wear-and-tear failure. You can always take them out and drop them into a newer, more powerful build and save a bit of money in the long run, rather than finding yourself in a situation where you want to upgrade your CPU and are falling short on power
Also if you're getting an aftermarket cooler then forget high-profile RAM, it doesn't do much, if anything, and can sometimes get in the way of the cooler, especially if you're using 4 sticks instead of 2.
That being said, make sure you get your RAM in a pair, rather than a quad setup. Leaves you room to expand in the far future
Also getting a modular PSU means you won't have ten billion spare cables arsing about in the bottom of your case that you aren't using - Corsair does some great ones. Pay attention to the Bronze/Silver/Gold/Plat classification, its related to the % power wastage and AX > HX > RM
For the Case consider portability, if it's a big case with a lot of weight, how will you pick it up and get it to your car comfortably etc. It's the little things that make the difference between you loving your machine and just being lukewarm about it - take advantage of the customisation freedom!
p.s. LinusTechTips did an excellent video on how you can use a HDD and SSD in conjunction to get faster run speeds with the larger storage space, rather than having them sit standalone in your machine.