Do you like solo travel? Have you done it? What cities/countries are good for solo travelers?
Even though I haven't done much solo travel, I enjoy it the few times that I went alone. The best thing about going by yourself is that you have to compromise. You choose to see and do the things that you are interested in. When traveling with others, especially girls, you end up wasting a good amount of time at malls.
Japan is a perfect country for solo travelers. The country is very safe; the crime rate is extremely low. Room prices are based on the # of people. Many Japaneses travel alone in Japan, so it wouldn't be uncomfortable eating alone at restaurants.