Hands down gen 3! The graphics were a huge step up at the time, from vibrant colors to hot springs and cable cars. I loved the previous gens, but this was huge to me. Not to mention the introduction of contests, bike mechanics, differing storylines, a rival who wasn't mean, and secret bases. While I enjoy the newer games (not so much dia/pearl or bw) I think it's going to be difficult for me to have a new favorite gen!
