Johto. Forget the long filler stretches blah blah blah, there were some genuinely good fillers found there, quite a few of which had real emotion and a valuable life lesson. The original trio was still together, and TR was still funny and had all their old Pokemon (minus Lickitung and plus Wobbuffet after a while).
I am the current leader of Save Our Voice Actors, a Pokemon fan group supporting the voice actors in the anime dubbed by 4Kids (seasons 1-8). Our goal is to provide The Pokemon Company international with encouraging feedback in support of returning the main cast members. If you're interested, please visit us at facebook.com/saveourvoiceactors