Within the past decade, gene therapy strategies have come to the forefront of novel therapeutics. Tremendous advances in vector technology along with deeper understandings of vector biology and the molecular mechanisms of disease have significantly advanced the field of human gene therapy. This manuscript will discuss the viral-based subset of current gene transfer vectors. In particular, the most established viral vectors to date, including parvovirus, adenovirus, retrovirus, lentivirus, and herpesvirus-based vectors, are described, as well as the current innovative improvements being made to each. From past experience, it has become evident that in addition to optimising the vectors in terms of transgene expression, minimising vector-related immunology, and vector production, methods of vector delivery resulting in optimum vector transduction of target cells need to be established. This review will also illustrate several current improved physical delivery systems for optimal vector administration.