Tsubasa if I had the ability to travel between worlds like they do I would never grow bored. Otherwise pokemon because the idea of a world where you could build a business on something you find roaming around in the grass is AWESOME, and you really could build a business on just about any Pokemon, Caterpie, a business making threads, garadose, a demolition or a ferrying business, charmander, well he's not quite a business but he could help keep my out house warm constantly...
I might also move into outlaw star/cowboy bebop or spice and wolf, although I don't know what I would do in those worlds...
oh oh! I know! .Hack, a world where the greatest video game of all times exists, oh wait then I would have to deal with internet people...