Skies of Arcadia Legends - Yeah, sure, it was a remake of a Dreamcast game with a bunch of other stuff that wasn't in the original game, but it was a good RPG, the characters were pretty likeable, the locations were colorful and varied (compared to modern games, I could crap myself just for seeing the colors blue, green and yellow in various areas), everyone's stories get wrapped up nicely and it is set up pretty well for a sequel. I mean, yeah, the game wraps things up almost TOO well (as far as the main characters go, anyway) and by the end the whole world is explored, removing that whole "exploration" aspect, and there's really not much of a bad guy for the ending, Valua's defeated and under the rule of its prince who was following you around from about the halfway mark. Really, Skies of Arcadia Legends CAN come up with a competent bad guy by using the old cop-out idea of "set it in the far future/distant past." Even so, Skies of Arcadia Legends was a great game and I'd love to see a sequel to it.
Psychonauts - Okay, now this one is the perfect candidate for a sequel. It ended on a cliffhanger, the first game was great (except for some spotty platforming now and then (and even then they were great) and the occasional easy boss fight), the characters were extremely likeable, the jokes were funny and the situations and scenarios were great. And let's not forget that it's one of Schafer's titles, and they're always good (yes, I enjoyed Brutal Legend). Like I said, the first game ends on a cliffhanger, leaving it in a perfect place to pick up a sequel. In fact, Double Fine's even hinted at a Psychonauts sequel on their website. Now if only those magnificent bastards would announce it...
Banjo-Tooie - Banjo-Kazooie...now this was a fun series. The first game was huge, the second was massive, so why a third? Well first of all, I completely disregard Nuts n' Bolts as a legitimate Banjo-Kazooie sequel. Second, Gruntilda clearly states that she'll get even with the bear-and-bird in Banjo-Threeie. Rare, come on. MAKE IT!