I grew up in the Norfolk/Va Beach area and you should know the public transportation is abysmal. You will have to have a car if you plan on going anywhere out of walking distance. If you live in the downtown/ghent area, you will be able to walk to some of the amenities you need (restaurants, bars) but most likely you will need a car to go anywhere else. The Hampton Roads area is not really conducive to public transportation (it is mostly suburban and too spread out). What bus system there is, is poorly planned, not very widespread, and poorly maintained. They are currently building a light rail system that will service downtown Norfolk and parts of Virginia Beach but it is far from completed and is more designed for commuting to and from downtown not within the downtown Norfolk area.
Driving in Hampton Roads is not as bad as many natives say. It has a lot of bottlenecks (tunnels and bridges) so during peak/rush hour times it can be unbearable (it once took me 2 hours to get through the Hampton Roads Bridge Tunnel at 4 in the afternoon. Who commutes at 4 in the afternoon?!). But the drivers are not as insane as many other cities so driving is safer. And parking is fairly easy to find, most of the time for free. Using a bike to get around the downtown area is feasible.
In terms of the military presence, it is obviously a big part of the population in the area but it isn't a detriment, in my opinion. You will see a lot of people in uniform. The military is just an omnipresent part of the area that eventually you don't even think of as unusual.
The nightlife in the area is what you make it. There are some great restaurants and bars in Norfolk and Ghent (which has a more Indie vibe). I would suggest avoiding the clubs on the Oceanfront in Va Beach (lots of barely legals and sailors on leave), but that is just my personal preference. The arts and entertainment options are great. Norfolk gets a large amount of touring bands, shows, and comedians (I saw John Stewart there this fall). The outdoor opportunities are also great (as mentioned previously the beach, Back Bay, Seashore State Park, etc.).
Hope all that helps.