You are best to choose a dark color and I recommend black as it is easier to match blacks than most other colors. The color black is a classic and will stand the test of time.
Grays are also readily available and modern right now. Choose a suit out of a fabric that is smooth and easily maintains it’s shape. It should look good no matter the season. This suit should be easily worn to work or dinner parties. Here’s some of our favorite tall suits and separates.
Long Tall Sally has a very nice selection of tall suiting options including jackets, pants and tall suit skirts.