I encourage you to sample a variety of brands and see what you think of them and how they work for you. If you have a local distributor where you can do "Will Call" pickups rather than paying for out of state shipping, I would take a close look at what they carry.
For modern fashion cuts, I like Next Level Apparel. I switched to NL from American Apparel after AA went bankrupt the second time and Gildan bought them. Tultex is TSC's house brand, and their attempt to imitate American Apparel. I have not tried them, so maybe you should
For a heavier, boxy, old-school T-shirt, I like Hanes Beefy-T. It is ringspun cotton and a finer weave, so is softer than Gildan's version of this style.
For hoodies I like International Trading Company, S&S carry them. They don't skimp on the cuffs and waistband, nor sleeve and body length.
EDIT You mentioned heather colors. These typically have a high polyester content, which can make for problems depending on how much heat your transfers require.
For modern fashion cuts, I like Next Level Apparel. I switched to NL from American Apparel after AA went bankrupt the second time and Gildan bought them. Tultex is TSC's house brand, and their attempt to imitate American Apparel. I have not tried them, so maybe you should
For a heavier, boxy, old-school T-shirt, I like Hanes Beefy-T. It is ringspun cotton and a finer weave, so is softer than Gildan's version of this style.
For hoodies I like International Trading Company, S&S carry them. They don't skimp on the cuffs and waistband, nor sleeve and body length.
EDIT You mentioned heather colors. These typically have a high polyester content, which can make for problems depending on how much heat your transfers require.