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.
When it comes to scent, there are basically two types; those that attract and those that mask. I've tried both on many occasions. There are lots and lots of "doe in heat" scents, designed to attract a big buck into range. I've also used a "cow in heat" scent while elk hunting.
Another scent would almost be better named as a "coverup smell". The main goal is to cover up human odor or mask it. Though I don't believe you can ever totally eliminate all human...