When I was very little Bill Nye the Science Guy was my favorite.
Loved Connections.
How It's Made, How Do They Do It, etc. are still my favorite things on TV besides Top Gear UK.
Modern Marvels is good when it's not about food.
I liked Mythbusters the first season but agree that the myths got less and less technically interesting, more gross with some explosions thrown in.
But I really liked Kari.