I am a woman. I'm also married to one.
Cooling is easy. Just put in a few case fans, three is sufficient and a CPU cooler. Nothing fancy is needed generally and most high-end or gaming cases come with in-build fans. My Fractal R5 has three built in and great airflow regulation and I added a Noctua CPU cooler on top of that. I heartily recommend checking out Fractal Design if you're building a desktop, though as @Parthu noted you probably don't need one for trading.
Define R5 Black
Above 32gb RAM anything additional is going to offer negligible benefits at best. Really you don't need 64 gigs of RAM. My work computer has 256gbs, and even that doesn't get close to being maxed out and I'm running a multitude of advanced military simulations and design software, usually simultaneously. If you're looking for speed for trading applications then CPU or GPU are better alternatives to poor money into. RAM ensures you can run applications, not always run them faster though. And again, anything above 32gb offers negligible benefits unless you're planning to run an entire suite of processes at once.
Your processor wont need an upgrade for a while that's for sure. Me jealous.
SSD's do run cooler, yes, and overall they're a better, but more expensive versus HDDs. Highly recommended for gaming due to their transfer rates, and good in general for booting an OS.
No SLI? Blashemy.
I'm joking of course, that's a boss GPU. But two is better.
And remember the golden rule of PSUs. 200 watts of overhead minimum. More is better. Calculate the required minimum of power and get a PSU that's rated for 200 watts above that. For my desktop I use an 850 watt PSU.
@Parthu has some good advice though. For your needs that setup isn't really necessary. That's a hardcore gaming rig, or for development/simulation nerd. For a trader though? It's excessive. A nice laptop offers both strength and mobility, at the expense of future proofing as upgrades aren't often an option due to OPM designs.
Civilian PC architecture isn't my strong suit unfortunately and I don't have the liberty to talk defence computing in depth with you guys. I'll try to goad Kat into joining us here, she's a super computer geek and hardcore gamer. PC parts are more her thing.
I'm not surprised. All interesting women turn out gay. It's like god never wanted me to have even a slim chance with them