What makes a boxing shoe?

This is a Nike Free 5.0 TR Fit 4. It coms in a billion colors and looks pretty darn cool.

This is a ASICS Gel Fortius TR. It's less flashy and comes in less colors than the previous shoe, but is a little cheaper.

Nike Studio Trainer. Less color options, lower price.
I've been practicing in a pair of beat up running shoes that I've used for so long that the sides are starting to split open. I'm fast approaching the point where I'm willing to invest in some new shoes. I've had a couple practices that have left me with some ankles the next day.