Is Oakland safe? Unequivocably, yes. As in any big city, most of the crimes against persons (murder, robbery etc.) take place in poorer neighborhoods. The average person has no reason to head to the these areas; tourists will never see them!
The only two remotely risky areas listed in my journal - Downtown and Lake Merritt Park - have both made great strides in making people feel safer at night. They are well lit, even if not well populated, and only average safety precautions need to be taken - the kind you would take on ANY vacation. I've been in these areas of Oakland after dark hundreds of times, and haven't been so much as threatened by anyone.
Montclair Village, Rockridge, Jack London Square, the Grand Lake/Lakeshore district, and Piedmont Ave. will all remind of your home towns, not of the Oakland you think you know from the national media.
Shrug off your worries and enjoy yourself!