The current generation 100 ISO film from Fugi and Kodak are all very good.
Astia 100F is wonderful, as is Velvia 100F, both have virtually no grain (I know this is heresy, but I like the Velvia 100F over the the old Velvia 50 and the recent Velvia 100). Provia 100F doesn't do too much for me, however. The new Provia 400X is an improvement over the old 400F and great if you need 400 ISO.
The Kodak Ektachrome 100G and 100GX are no slouches either and are as good as, if not better than, Provia 100F and Astia 100F (just as fine grained, and what grain is there is a bit nicer). The slighter warmer toned 100GX is nice to have.
B&W -- Fuji 100 Acros is great and hard to beat. Ilford Delta 100 is also nice, and in appropriate situations, Ilford Pan F.