My square cakes are never crisp and straight.. I google other cakes and the edges are amazing....I am using the Fat didios 3 in pans... does any one have any advice?

its all about whats on top of the cake - ganache is 100% the best thing for crisp edges (in my opinion), it sets firm so you cant smoosh it when you put the fondant on.
you can get crisp finishes with all bc, it just takes pratice and technique.
putting fondant on top of bc is not so easy, i feel, because fondant is heavy! so u need a nice stiff bc (possibly refridgerated, if that works for you- theres a risk of air bubbles in ur fondant tho), and a gentle touch with the fondant. its very much about practice too!
xx

http://cakecentral.com/articles/109/how-to-frost-a-square-cake

This shows how to get crisp edges. But if you are covering with fondant, i think the weight mushes it down. I'm not that great at it either, and practice is the best thing i think

You chill your iced cake before putting fondant on. This is how you get sharp corners, without using ganache.

I agree with Karmacakes. I use SMBC under fondant and refrigerate it prior to covering and it gets really firm. I always cover my cakes straight out of the fridge and then put them back in right after covering so the fondant really sticks. Works every time perfectly -no air bubbles ever.

Magic Line pans and either chocolate ganache or white chocolate ganache instead of SMBC or BC under your fondant. Let it set up in the fridge until really firm and then mist with a spray bottle to get the fondant to stick to the ganache. Works every time.