Real storm windows – They're a little hassle but I'm replacing my “modern” storms with the old wood frame ones.
Jim Korman
Buy good quality windows, like Andersons. I have Pella windows and if I had to do it over I'd go with Anderson, as they are a bit easier to finish.
Bob
Good thermal panes with argon gas, double or tripple lites, low-e coatings. Vinyl or vinyl clad wood frames.
Dave Lag