I've used Mobil 1 0W-30 for my last 4-5 oil changes. It allows for even less wear on cold-starts than 5W-30 while retaining the same viscosity at operating temp. Some would argue that it contains VI improvers that may cause it to wear out sooner than 5W-30, but I change my oil every 3000 miles, so I'm not worried about it.
I also switched my gf's '99 Corolla over to 0W-30, which had very telling results. When it was running on 5W-30 conventional Toyota oil, it was sometimes difficult to start on cold mornings, and it was always rather noisy until warmed up. Ever since I switched to the 0W-30, it has started perfectly every time even on the coldest mornings, and has idled more quietly. It's good stuff.
