All-seasons will obviously not be as good as dedicated snows and dedicated summers, but once you get past that, there are several good options. You'll lose some edge when it comes to turn-in and probably ultimate grip, but you'll most likely gain ride comfort and the obvious all-season and light-snow capability.
Tire Rack tests:
http://www.tirerack.com/tires/tests/testDisplay.jsp?ttid=102
http://www.tirerack.com/tires/tests/testDisplay.jsp?ttid=87
I've read and heard good things about the re960. My mom is picking up a set for her CL, so if you're still undecided, I can give you a better idea in a few weeks.