In proper contruction with hardwood floors, the baseboard goes down before the floor is put in (so do the door casings), so there's 3/4" of bsbd. hiding beneath the floor level. If that's your case, I'd advise leaving the baseboards alone. It may also need a channel routed into it to accomodate the wire.
The crown's a better idea, but, if you've never done it, and the walls are not 180 degrees with true 90 degree corners, it can be an aggravating bear of a job.
It should cost about $4-500 to crown a 12 x 12' room, with (non-exotic profiles) materials included. That doesn't include filling, sanding, priming (if you used unprimed stock), and painting.
Crown almost always needs all of its edges caulked, which will leave a white edge on both the ceiling and the wall, which will need to be re-edged (painted).
Hope that's some help, Ken.
