Either of the bullets in the calibers you mentioned will work. Black bears aren't all that hard to kill, but you do want something that will penetrate through and through while still giving good expansion. Nosler Partions are a great choice and I will be using them on my bear hunt next week. I hope you have a great hunt.
I'm hunting Saskatchewan black bear May '08 - use your BOW
Everyone I've talked to says that black bear (over bait) is a definite bow hunt. Provided, of course, that one is proficient with a bow (min. 160 lb. draw / 125 grain non-mechanical broadhead).
From what I've researched, many good options on rifle for black bears - 30-06, 7 mm magnum, 300 mag or 300 WSM plenty powerful - should be at least a 180 grain - nosler partition a good choice. I like the Accubond round personally - took down a 1,200 lb. moose in 2004 with one well-placed shot.
Understanding wind currents and thermals in hilly, broken terrain can often be incredibly frustrating. I've found that collecting and storing milkweed seed pods during the late summer has made me a better hunter in the bluff country that I hunt. These little feather like seed dispersers will float on the lightest of air currents and will show you what the wind is not only doing right at you're location but more importantly down range. I like to use the off season to float them...