Diversify...Diversify
The treeman has a good handle on this. Diversify, unless you have a specific need or market for just one or a few species. I like the idea of Ginkgo and Bald Cypress interplanted as they are perhaps the most reliable and sturdy trees around. They hold up to storms quite well and once established are both very drought tolerant with few pest and disease problems. Dawn Redwood is good also but not as drought tolerant as the previous mentioned trees. I would place it in an area that is more moisture retentive. Maybe a low lying area that receives some run off during rains. I say don't rush into it. Take your time and perhaps place about 10 or more different species in your arboretum. A few hard maples would be nice. Plenty of Asian Maples that are tough and beautiful. Maybe some Japanese Larch (same moist conditions as for Dawn Redwood). Nyssa sylvatica is a good hard wood to place in either a rocky well drained or a moisture retentive area. Good fall color. Nutall and Overcup oaks are nice. I recommend staying away from Pin Oak. Sawtooth are said to be invasive, avoid it. Throw in some Kousa Dogwood and some Magnolias(both deciduous and evergreen). Trident Maples, Shantung Maples, Chinese Lacebark Elms, Zelcova, Pseudolarix amabilis, etc. etc.. Japanese Maples...hundreds of different cvs. Plant some relatively rare trees. If you don't fall in love with them you can sell them, when mature, for big bucks. I wouldn't plant too many White Pine but would incorporate different Spruce, Fir and other conifers. How about China Fir, Cunninghamia lanceolata. True Cedars and Sequoia sempevirens. Zone 7...right? If you just go out and plant a bunch of easily obtained White Pine or another species, I believe that one day you will end up wearing out a chainsaw or two and wasting a lot of your time.