Good size for snow tires for LS

[04SCTLS]

I'm going to be driving the LS through the winter this season and want to put 4 Blizzak snow tires on it and 200 lbs of sandbags in the trunk.
I have an extra set of 17" factory 8 spoke chrome rims which originally came with 235/50/17 tires.
What size would be good. I'm thinking 215/60/17 for a narrower tread.
Thanks

 

[SPY]

I just bought 225/55/17 Bridgstone WS-50's. They have the deep snow rating and were only $99 each at tirerack.com