CONAN O’BRIEN grew up watching DAVID LETTERMAN and JOHNNY CARSON so the boyish looking late night talk show host knows the legacy he inherits when he succeeds JAY LENO on The Tonight Show.  Don’t expect O’BRIEN, however, to have the same kind of highly publicized rivalry with LETTERMAN that LENO had.  The Generation X’er has only kind words for LETTERMAN and it looks, at least on the surface, that this competition will have a more cordial interchange. (CLICK ON THE MEDIA BAR BELOW)