A few years ago we replaced the old windows on our house, or at least most of them. The windows that were original to the house were bronze multi-paned aluminum with separate storm windows, at least on most of the windows. They might have been nice when the house was built, but the plastic stops were cracked or missing, and the storm windows were installed so poorly that spiders had set up housekeeping in the airspace between the windows.
We replaced with NT aluminum windows. They are double-glazed tilt windows, well sealed and easy to clean. However, one of them has begun fogging between the panes. *sigh* At least they have a lifetime warranty.