It also depends from your TV:s ability to use interlaced signal. That differs a lot between TV:s. Basically upscaling and interlacing is the worst possible situation. I would say using 720p would be optimal to your 720p TV.
But, maybe others know better than i do.
Ei Kiinasti.
Eikä Japanisti.
Vaan pannaan jalalla koreasti.
Nintendo games sell only on Nintendo system.