I don't know if this exists, but you know those companies that take your old bathtub and re-glaze it so that it looks newer (I think they can even change the color of the tub)? Maybe you could get your toilet re-glazed so that it has a fresh finish and stuff doesn't stick to it? Like I said, I'm not even sure if that's an option or if it's just a bathtub thing. Might be worth checking into though, and would probably be cheaper & easier than installing a whole new toilet. You might even be able to get a glaze kit yourself and do it. Just a possibility.
And for what it's worth, I feel for you. We bought our house a few years ago and it's ugly, particularly the bathroom. The previous owners last re-decorated in 1977 and they loved pink, so my toilet is ugly 70's pink - like a salmon pink color, yuck. And it doesn't work great, clogs often and requires a lot of cleaning too. Someday we're going to remodel the bathroom (I have a LONG wish-list for that, ha ha), but until then I'm stuck with a hideous old icky toilet too.