Well, been using gmax for a while, thinking of moving to Blender (Heard a lot of good stuff about it)
I know about The-Blueprints, it's a great site, but if you're looking for aircraft blueprints (I concentrated mainly on aircraft modeling, which was probably a mistake...),
airwar.ru has some very high quality blueprints which are much more detailed than the ones on The-Blueprints (Even though they are probably harder to use for that reason too...)