Just interested - which accessory (lenses excluded) do you consider most important for your spanking-new Nikon D200?

When I got my Nikon D70 back in Mar 2004, the first thing I bought along with my camera was a Hoya +4 Closeup Filter, as I wanted to do pseudo-macro photography by slapping that filter onto my Nikkor 50mm f/1.8 lens. The combo couldn't touch my Coolpix 4500 for macro capability, but it was better than nothing.

So back to you - what else are you intending to buy?