Definately Pokemon. Now, I never really watched Digimon a lot, that said, as I recall, the world was generally in grave danger, and they were all fighting to save their whole world or digiverse or wherever the McShit they happened to be fighting at the time.
Pokemon (which I only ever saw maybe the first 30 episodes or so, as well as playing a lot of the games) as I recall never had that whole "the world is ending if YOU don't do something about it" thing. I mean, maybe Ash had to save it in the movies, and I guess in the later games they got tired of Team Rocket and moved on to people with somewhat more dasterdly plans. That said, the impending sense of doom is gone, and I like that. I'd just want to go and chill with my pocket monster, because really, battling probably wouldn't be my thing. Plus, and if there are any rabid Digimon fans who feel the need to correct my assumption then go ahead, but as I recall in Digimon you only got the one Digimon... I don't recall them even really having had that much choice in the matter. But in Pokemon it's just like "oh hey, there's a whole world of these little fuckers, pick whichever one you want." I kind of like that ability to choose.