Right off, Peter Strauss looks like Kennedy material. There is the handsome, athletic body (encased in a dark blue suit, tasteful pin-stripe shirt and faultlessly-knotted tie), the jabbing, nervous gestures, the quick boyish grins, together with an occasional gray-green stare fired right down your gullet. The background isn't bad either, what with a summer spent in Europe as a kid, and four preppy years at some place called the Hackley School for Boys. But any similarity ends there, insists 30-year-old Strauss, whose acting star seems neatly poised for blast-off into tthe stratosphere. After all, he only has to play legends, not be them.