Absolute positioning, what is the point?

Ok maybe i'm missing the bigger picture here but I just can't see any reason for absolute position other than allowing you to put the main content of your webpage at the top of your code so that it loads first.

So far I havn't found found anything I can't do by just floating divs. I sometimes use relative positioning for fine tuning bits however.

What type of situation would warrant the use of absolute positioning?

Does anybody know of a good source/guide on the use of positioning? What are the limitaions cross browser? Every time I've tried to use it I end up with divs all over the place, not doing what they're supposed to and so I just revert back to floating them and it's all good.

Could be a good article for somebody to do for A Padded Cell