I haven't played many ROM hacks for the games, but I did play through Pokemon Insurgence a while ago and was quite pleased with it. The game has new mega evolutions, delta pokemon (which Nintendo are officially bringing into the video games this gen as Aloha forms), internet connectivity, friend safari's, challenge modes, items that replace HMs, and a good bit more. They also went for a more 'mature' story, which some will probably appreciate, though I was largely indifferent to it. Enjoyable game; probably worth checking out for any pokefan on a PC.