@haney I love building PCs. What software do you use for your music production? If it’s known to run better on Macs, you might consider those, but generally you can get more bang for your buck on the PC side of things. A good place to help you pick parts is the Tech Report System Builder’s Guide. LoL isn’t all that demanding even at the highest settings – I’d say something like a Core i3 w/ 8 GB of RAM (mainly for future proofing / RAM is cheap; 4 GB should be more than enough for what you’ve stated) and some mid-range video card – Geforce 750 Ti or 760, maybe a Radeon R9 270? Something like that.
If you’re looking to save money, I’d say take the Tech Report ‘Budget’ Sample build ($570), change the 4 GB of RAM to 8 GB (+$35) and go with the Core i3 over their Pentium (+$55) and consider changing out the 1 TB mechanical drive for a 256 GB Solid State Drive (+$55) for a decent $715 machine.
If you don’t have a monitor, I really like this 23" 1080p IPS display. It’s $170, but it’s a pretty nice monitor. We’ve got a few around the building here at work.
Or, if you’d prefer a laptop, the Lenovo Y50 is $1100, but a pretty good machine!
A guy I used to work with actually does work for Intel in their lithography department (i.e., making the chips smaller – keeping Moore’s Law on track). I do not envy him at all right now, haha.