I've enjoyed playing with Foma in 100 speed (Sorry, Mike!) in 35mm. Cheap, fun. Grainier than most contemporary films. I've done a few rolls of 400 in 120 but I'll be damned if I remember much of anything except that blue backing and the curl!

If you're shooting 35mm, why not Arista Premium? Cheap Plux-X and Tri-X.