Go over to the Camera Store downtown, and explain what you're looking to do with the camera and what your future pictures wants/needs are and they will help set you up with something that will work best. Try out as many cameras as you can, and see what's available for accessories too. Find something that you're comfortable with, and feels right when you're holding it. Try the menus, and see what you think. Personally I'd stick with Canon as they're my personal choice when it comes to cameras, but Nikon is on par and it really just depends on what you like.
When it comes to Megapixel....don't worry about it. There are cameras out there that have well over 20mp, and while this is impressive....my Canon Rebel has only 6.3mp and I rarely ever actually use the size of picture it takes at full resolution. This is due to the physical size of the sensor. Most point and shoot sensors are lucky to be 3/8"x1/2", while DSLR's usually have sensors in/around 7/8"x1 1/4" so the size and quality of the image is already much better.
Personally...I'll be going with a Canon 5D MkII for my next camera, but at over $3000 for the body alone, I doubt that it will be what you're looking for.