This is a great idea, and I'd buy 10 or so. It would also be nice to eventually see other denominations such as 50, 200 and 500 mBTC.

One downside of the holograms on casascius coins is that they're much less tolerant of the general handling and abuse that comes from being carried around in pockets and stuff, but I suppose there's not really much that can be done about that. Maybe have the hologram sticker recessed into the coin by a small amount (the thickness of the sticker) if it's not impractical.

Would faint latitude/longitude lines on the world map look good? What's the deal with the people around the edge? What will the other side look like? Reeded edge or plain?