6'4". 290 lbs. Out of shape college athlete.

Those are things to look at closely. Most bikes aren't made for guys your or my weight, let alone for people who have athletic backgrounds at those sizes. Your weight is gonna be hard on wheels, your strength will be hard on the drivetrain.

I don't think a discount store bike would survive very long. Ignore all the problems with ill-fitting frames from department stores. You're gonna take out everything on the bike. A lot of lightweight, fancy race bikes wouldn't survive you either. But thankfully there are a lot of bikes that will work fine, though some of the stock components (wheels) may not last that long before you replace them with stronger ones.

Spend some time in the Clydesdale forum. You'll get better advice there on a bike will handle your size. In the commuting forum we basically just argue about road bikes vs hybrids vs mountain bikes and push racks and fenders like we've invested our 401k entirely in Tubus.