I usually do magic loop on a single long circular. I do have to use DPNs when doing the top of a hat or a mitten thumb, but I dont enjoy it at all! I find DPNs a little stressful when trying to manage all the stitches and keep them from sliding off the needles.
Circular needles for sure. It takes much less space, and I have interchangeable ones that make it easy to have various sizes without having to get all varieties.