When I shoot color, I like relative neutrality. Kodachrome 25 is the only color film I really like, but alas there are only 20 more rolls in the freezer, and I shoot less and less 35mm (except for birds, which require faster film). If I'm going to bother to carry a tripod, I might as well carry a bigger camera.
So I use Kodachrome 64, Provia 100F pushed one stop in flat light, and Provia 400F in 35mm for birds. I like RMS and Provia 100F for medium format landscapes, birds that can be photographed with medium format, and such, and some Porta 160NC for people photos. In large format I like Astia for portraits, and I have some VPSIII in the freezer also for portraits (when that runs out, I'll move to Portra 160NC), Astia or Provia 100F for landscapes, still life, and architecture.