Budget?
The Deepcool Matrexx is popular for the RGB-bling, but not the best airflow.
www.newegg.com
Unfortunately, airflow/cooling and aesthetics/RGB are in opposing corners a lot of the time.
You might do well to consider a solid airflow case & add RGB elements (fans, strips etc) to it.
Something like a Meshify-C? Still nets you tempered glass, and put a couple of LED fans or a strip etc inside, maybe?