What kind of motion graphics are you planning on working with? The first thing you might want to think about is if you are going to be doing a lot of live action video FX or something else within the range of motion graphics in general Some apps do the generalist thing better and would be better suited for a smaller company that dabbles in a bit of everything. Other apps are more specialized so it is important to know what kind of clients/work you might be getting into.

I am playing with Nuke now and I am spinning on my neck on the robustness of it. I can wait until build my Apple editing suite and use nuke as my main compositor.

Nuke of course is the current flavor for 3dcomps . AE does 32 bit easily, but you need Fnord ProEXR to make it fully usable. I predict 3D comp tools will be in not too distant AE upgrades. :)