Men's shirts - Hanes Heavyweight Ts, Hanes Beefy-T, 100% preshrunk cotton
Women's shirts - Bella "babydoll" style, 100% preshrunk cotton
Note that the women's shirts are fitted t-shirts and are much stretchier than regular shirts. As a result, if you enjoy your shirts snug, you can generally wear a size smaller than you normally would (medium instead of large or small instead of medium) and still have it fit nicely.