I wouldn't say so, but that is only based on what I know about hard drives in general, not the specific models used in the Mac Pro.
As of yet, we haven't seen drives above 1TB proven to be... safe.
Terabyte drives are very stable, 1.5... NO.
The WD 2TB drives are looking good, though. If they keep up their current track record, I'll be picking one up in the summer when they get a little cheaper.