On the DMPC: Currently, I'm going to be running a game with only two players, though they will be using Gestalt characters from the Unearthed Arcana. In this situation, if I'm missing a certain class (such as cleric), I'll stat up a quick NPC. He'll technically be a PC, but I'll run him as more of a henchman, where he doesn't make any decisions, or take any actions unless the PC's ask. This way, I won't be tempted to give away to much information (and yes, if I think that I've written a particularly good adventure, or found a good module, sometimes I want to share the coolness with my friends so much that I blurt things out).
On Minis: Limited funds and space. I do have a few of the D&D minis, and I hope that I'll be able to use them as something more than decoration in the future.
On Battlemats: Any good sites out there that carry any, preferrably dry-erase mats or something similar? Thanks.