I have the same car and bought 17 rims and summer performance tires. I'm using the stock steel 16" rims for winter tires and 205/60 16 is pretty close in diameter as the stock 215/60. You'd be better off going with a 16 winter combo as it's much cheaper than the 17 option. No problem clearing brake calipers since 16's are stock for some of the models and there's no upgraded larger brake calipers on the Altima (exception SE-R)
I'm going with Kumho's KW17 as it's probably the best bang for your buck for city winter driving especially if you get it through Tire Trends. What a steal. Cheaper or as cheap (in cost) than Crappy tire winter tires/ H rated for better handling and 13/16 tread depth. The combo of living in high elvevation in Bungcouver, wet snow, long wheelbase, and no ABS (too much of a cheapskate to pay for that $1500 "option") makes winter tires a necessity for me. Just procrastinating until after 3rd snowfall (Since it's already snowed twice where we are)
Stock Tire - 215/60R16 Tire 1 - 205/60R16 Tire 2 - 205/65R16
Speedometer Difference: 1.822% too fast Speedometer Difference: 1.299% too slow