Hit up PC part picker. But, will RGB impress the friends or a rig that can perform? What does RGB matter if you don't have performance? A sweet case and tastefull RGB can go far!
NZXT has some pretty nice stuff as well as almost all motherboard vendors with RGB ports right off the motherboard. RGB can get spendy quick. For the same price of a good lighting kit, you can easily upgrade your CPU or even GPU to the next performance level in some cases.
So, before you decide on RGB, what is your build? Build it out on pcpartpicker.com and toss a link in the comments. Community can help you from there here at Tom's hardware.