Life-of-copyright contracts are standard in the commercial publishing biz. They're only a problem if they're not balanced by a good out-of-print/rights reversion clause, stating specifically when and how a work will go out of print (ideally, this should be tied to minimum sales figures) and how the author can regain his or her rights.
That said, life-of-copyright isn't always appropriate for smaller, digitally-based publishers. A limited term--three years, for instance--is preferable.
- Victoria