Do it yourself

I just took off the aluminum siding in my house, that had been put on in the seventies and I now need to paint the clapboard that was under it. The architect that I hired recommended Para Paints, an environmentally friendly Canadian paint which I found, is expensive as ... I was going to use "Colour Your World" Paints, which I used before for interior paint and was very impressed with. I was told by a friend that this brand name was not good in exterior paints. She actually recommended CIL. Now CIL, over here in Canada is sold in department stores, is cheap, and I thought it was not particularly good. I would like to have some recommendations from people who have painted their clapboard houses. What brand names have you tried and that you feel are good? Thanks a lot for your help. Ana