So I have heard a lot of debate about absolute positioning and I was wondering what are the main drag backs to this, other than everything being locked in the corner (yes I know you can write code to center this)?

AFAIK the main drawbacks with AP elements used to be poor browser support for it. Not so much of an issue now .

An AP element has no need to be 'locked' to the screen, it is absolute only to its containing block - put it within a relative positioned element and it will move with that element.

Great answer. It's one of those tools that's appropriate in some situations but not in others...

It can be difficult sometimes to mix the flow model with absolute positioning, but if you peg them to whatever container they live in, it can be just the tool for the job sometimes.

IE (what else ?) has some issues with absolute positioning. You might want to read thru this:
http://www.positioniseverything.net/posbugs.html and
http://www.positioniseverything.net/abs_relbugs.html

I was just wondering because I got in an argument with my teacher at school, and I really couldn't argue with him when he asked what the draw backs were.

For the most part, I can't see where a layout done completely with absolute positioning is necessary. It better and more flexible to use the normal document flow and use floats.

I normally only use absolute positioning for things like logos, or address boxes, small pieces really. I've never done a whole layout with absolute positioning and I probably never will.