well, the same things that are similar to ADD, seem to also allow bursts of very intense focusing. I am able to see things [in my mind] in 3-D in a way that few people are. So, as an engineer, I've used those abilities to design and analyze some very complex problems and have made myself valuable by learning how to do analysis and do model symulations of aircraft structure. It isn't easy, but if you want something, then you have to just stick to it and gut it out (like college -- was wasn't fun, or even remotely easy, but it was necessary). Sure, I'll always be a bit of a day-dreamer, but there ain't nothing wrong with that!
I do recommend that you do the toughest thing your mind will allow. The harder the problems that you can solve the more valuble you an be and the more you can demand ($) in the market place. It's not something I brag about on the board, but just to let you know as a freelance structural analyst I make over $200K a year, and when I'm working out of the country it can be from $250K to nearly $300K. I do work a lot of hours, but if you want to get ahead financially, you got to get after it.