Sometimes you just want to remove the skin. This will result in a more yellowish glow of the fire through the watery flesh of the pumpkin. The effect is nice and allows you to have three different tones (dark, light, medium).
To remove the skin, I like to use my router. I set the depth at 1/4 inch or so because the curvature of the pumpkin will actually allow the router to plunge more than that.
Using the router is easy because it has two nice handles. I grip it, and rip it. It cuts through the pumpkin skin like nobody's business.
The only warning I have is that the pumpkin flesh and skin will turn to goo. You can't blow it out sight, instead you may have to stop working to clean off an area.
For fine detail, I use a dremel tool. I have tried a few rotary tools without much satisfaction. I find the the Dremel "stylus" mode works well because it sits well in your hand and doesn't move around much. It isn't cheap however, it runs about $70 at your local home improvement store. Dremel does make a "Pumpkin Carving" bit, which is a soft-material carving bit. It is the only thing I use in my dremel tool.