Best router recommendations?

Could someone please clarify how to accurately monitor my router's signal strength? I am familiar with the process of entering the IP address into a web browser, such as 192.168.... and seeing values ranging from 40 to 50. Is that figure actually an indicator of signal strength, or does it represent something else entirely?...

I don't really need this... I ran the numbers myself and came up with about 70%, which I consider quite sufficient for my purposes...