I think most, if not all, geographic regions have their advantages and disadvantages. I've lived in California, ridden the Atlantic coast of Florida, ridden most areas of Michigan, upper and lower peninsulas, and spots here and there along the entire I-75 corridor. Like outashape, I ride a road bike, but will probably hit the trails one day soon on a hardtail. Just no place local to the metro Detroit area that I would consider to be worthy of making that change. Out west, or down in the Smoky Mt area would be a different story.
One of my favorite rides is the Horsey Hundred in Kentucky - particulary the century route. The first half takes you into the backcountry, big hills (did someone say Frankfort??), but questionable road quality. The second half takes you through some of the most beautiful horse farms you could imagine, gently rolling hills, and considerably better road quality. DALMAC still is my favorite multi day tour, though having done that 5 times already I am ready for something new. Spent several days last week scouting the Blue Rdige Parkway and the Natchez Trace Parkway, and drove the Smoky Mountain Parkway from Gatlinberg TN to Cherokee, NC. Looking to ride the Natchez maybe next year or the year after, Blue Ridge MAYBE a year or two after that.
Half the fun is planning the ride..... and swapping stories afterwards.
All in all..... Michigan has a lot of variety to offer. It is true that there are prettier and more interesting areas to ride scattered across the country - but don't discount what we have right in our own backyard.