Not unlike people, some plants look better undressed than others. I have always liked the look of Magnolia stellata, or The Star Magnolia, in the winter. It is compact with wonderfully meandering branches and smooth grey bark. An abundance of large flower buds, greenish and hairy in a good way hint at the profusion of fragrant white flowers that will festoon the naked branches early next spring.
One attribute of a good Bonsai is "taper" meaning that the trunk and branches start out thickest, then narrow gracefully and gradually through their lengths. What's aesthetically pleasing in a bonsai looks good on full sized trees. Look at the picture; that's perfect taper, not only in the branches, but also in its forked trunk...and it works! That tree looks good.
Garden Centers in the Washington area carry a variety of magnolias including the natives M. grandiflora, a large evergreen and M. virginiana, a smaller tree, semi-deciduous to evergreen with wonderfully fragrant white flowers in summer. A variety of Asian species, varieties, and hybrids are available. They're good plants for us, not minding our hot humid summers, clay soils, and unpredictable rainfall. The one issue that does come up is that the early flowering varieties are sometimes tricked into bloom by unseasonable warmth in late winter or early spring, only to be toasted by a subsequent frost. Well, sometimes you have to take chances for the big payoff. Or if you are of a more conservative bent, use M. x 'Galaxy', a USNA release that flowers late enough to miss almost all late frosts.