One of my only complaints about Ravenloft is that there hasn't been a decent poster map of the Demiplane of Dread since the first black box campaign set. The maps in the second red box campaign set were so-so, and the freebie map distributed through retailers as part of TSR's Gold program when the third incarnation of Ravenloft (the Domains of Dread hardcover) came out were not very good at all. Unfortunately, the trend continues with the d20 Ravenloft hardcover - a pullout map would have been nice (and much more useful) as opposed to printing it on the inside cover.
I would like to suggest you check out The Mordent Cartographic Society, a Ravenloft fan site that has some really nice maps done in Campaign Cartographer 2. The maps are in GIF format, so you don't need CC2 to view them: