Don't forget to clean your wiper blades when you do the glass... Good maintenance here will eliminate or help to avoid streaks and poor performance.
Of course, one ride to work behind a truck or bus (diesel engine) will mung things up again, but...
I'm noticing some serious spots on my glass too - I'll have to try out some of these suggestions. I used to just use a 3M "kitchen scrubber" sponge (with the green, rought stuff) and some hot, soapy water...