Hooked on CW !!

I avoided ham radio for 30 years because I didn't know code and wasn't sure I could learn it. I found a good computer program and was copying close to 10 WPM in five weeks. It was REALLY ugly for about two weeks but I soon found myself enjoying it - now I hate myself for not doing it sooner.

Oh well. Now, can some of you CW veterans answer something for me? I am about to buy my first rig and I have read a lot on what kind of equipment to buy. What is the rationale for learning on a straight key versus a "bug"? It seems most of the hard code CW types wouldn't be caught dead without a Vibroplex in hand.

Also, can somebody explain what iambic means when used to describe paddles? All the manufacturers seem to throw the term around without really explaining it and it is hard for a newbie to understand exactly.