I really like Blue and N as rivals. blue was always bragging about how tough he was and plus he's an original.
N is more developed as a character and he is very unique from the other rivals as far as his goals are concerned. I really felt for him and I liked how the development team always made sure N never had the same Pokemon each time you battled him.
I liked Blue from the manga better than the games, that's why I chose him. He actually becomes more mature and a better trainer. Plus, his charmeleon slices an Arbok in half.