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.
Bring them in on a string. I love this term, if you want to be successful on calling in Elk, try not to just sound like the other caller. We all laugh at each other when we are practicing Elk calling at home or while camping. When I first started calling in Elk, I had no idea what i was doing and it's funny how many I could call in. The biggest Bull that I have called in to date was actually my first. I was making cow calls and screwing it up big time. But it's obvious I didn't screw up...