Tons of people playing 40K regularly at Empire. Cant speak for IO from personal experience as its too far for me to travel (especially when Empire is so close to me), but i know they hold regular events, too, and that theres a healthy community out that way. Cant speak for Crusaders Retreat.
Also, theres been a resurgence in WHFB, so if Fantasy is more to your liking, tons of people playing it at Empire on a regular basis, too.
Best of luck, and welcome back!
A bad day of gaming beats a good day of work (or school) every time!