I'd love a page turning animation on the book.
Edit: It'd be cool if they do something, like firing unique projectiles that can activate events.
The book can be an encyclopedia.
OnBookHit > Client > Centerprint > "You can fix the car with 2 scrap metal"
The Pencil can be used for writing.
OnPencilHit > Self > SetColor > (Black)
The PDA can be a useful gadget.
OnPDAHit > Self > Disarm Mine
The Briefcase could contain mission-critical material.
OnBriefcaseHit > Minigame > Team1Win
The radio could work with the radio mod. I'm sure someone would be interested in scripting this.