Over the years, I've taken the same tactic and changed it up a bit. I still put diced potatoes into a gallon-size Ziploc, but now I often add a sliced onion, garlic cloves, and veggies. The good thing about this is that the potatoes, onion, and garlic serve as a versatile base for different veggies (or combinations of veggies): carrots, asparagus, bell peppers, eggplant, tomatoes -- whatever your heart desires, actually.
Tonight I wasn't in the mood for lots of chopping, so I decided to go for a decidedly basic version of this dish: potatoes, onion, and carrots.
Step 1: Grab a 1-pound bag of baby carrots, one onion, 7 cloves of garlic, and 5 smallish potatoes. Chop the potatoes (you can either dice them into cubes or make thin-ish slices). Put everything into a gallon-size bag. Pour 1/4 C olive oil, 1/4 C balsamic vinegar, and 2 tablespoons Italian herbs on top, and shake the bag until everything has an even coating.
Step 2: Put 'em on a tray, and throw 'em in the oven.
Step 3: Roast at 400 F for approximately 30 minutes. Halfway through the roasting process, run a spatula along the bottom of the pan to loosen and redistribute anything that might be starting to stick.
Step 4: When everything is cooked through, broil until the potatoes and veggies are starting to get browned and crispy. Remove from heat, plate, and enjoy.