If you want to keep a smoother ride make sure you get like an all season tire or something. Getting mud tires, they will be a little rougher ride and can hum on the highway due to the knobby part of the tire.
If you like it the way it is, I would suggest looking in craigslist for take Sahara take off's. guys upgrade there rims and tires all the time and sell the used ones. Great way to save some cash.
If you want black rims, and have deep pockets. Look at the XD Rockstars. Awesome rims and they look fantastic.