40K and AoS is played quite a bit in North Dallas, but not sure if that helps if you are South.
My favorite LGS is Texas Toy Soldier in Carrolton. Not only do they have plenty of tables and terrain, but most of the stuff is marked lower than retail, usually around 10-20%
Another option is Comic Asylum in Garland/Richarson. Not as many table and mostly just Comics and Card games. I am personally biking distance, but it's not my favorite LGS due to the lack of space and full priced GW stuff
Or Madness Games, which is pretty much just a much larger comic and card game store. I think they have nearly 100 player Magic tournies