How did you end up with a black suit?
My suggestion would be
- Navy blue
- "Heavyweight" wool (around 400 g/m²)
- Having a three-piece is good for winter, yes.
- Double-breasted if you trust your tailor a lot.
Note that due to the weight of the wool, this suit will be unwearable above 20 ° C or so. However, the maintenance will be practically none aside from brushing and the occasional pressing of the trousers.
If you are bit more adventurous, dark brown or mahogany in wool/mohair could be pretty cool for summer wear, or dark olive green cotton if you like wrinkles (slightly wider shoulders, longer arms and longer pant legs with cotton due to shrinking).