TCM
It's showing right now on TCM (Early Sunday Morning, August 24, 2014) as part of 24-hours of Ernest Borgnine movies. Their copy is in High Definition. So, you'd think an HD copy could be available at some point.
"I. Drink. Your. Milkshake! [slurp!] I DRINK IT UP!" - Daniel Plainview - "There Will Be Blood"