As a review unit, it should be in a "Just Works" state. No - or minimal - instructions, and the system should be already set up.
Include only one browser, whichever runs best, maybe two, Firefox because everyone knows it and Fennec, if it provides a great touch-interface. Provide easy, obvious access to the "app store" so other browsers can be easily set up. The reviewer likely won't, but he'll take a quick look at what other software is readily available.
Don't overload in games. A couple different emulators with a couple games each, whatever can be legally distributed. While the Pandora is in many ways primarily a gaming handheld, you don't want to focus too much on that. You want to highlight all of the different things it can do.
Christoph.Krn has it right, IMHO. Make sure there's solid, easily accessed apps handy for every sort of use - music, video, office, PDA stuff, etc.
Show that yes, this is a gaming handheld, but it's also a full desktop PC that fits in your pocket.