What makes a good Hi Fi rack improve your system.

Having currently got my amp set up on a glass shelf along with my turntable, I am after a good Hi Fi rack. One I want to centralise everything and have the Blu Ray, Amp , sky and turntable all together. There are so many options out there. Some have glass shelves some are Wooden. Also isolation is key. My question is the key factors they will help improve your systems sound. I'm based in the UK, so all factors to look at would be great. Even some brands. I'm hoping you can help.
Thanks in return.