Length, which directly relates to leverage force, is critical. My bedside prybar is as long as possible, since portability is not an issue. I don't think the different terminal configurations are vastly significant.

When portability is an issue, the prybar in Dougwalkabout's post reigns supreme. It is available in different sizes, down to keychain size, and they all are useful in many different contexts. I use them occasionally in archaeological and paleontological digs, among other uses....