And remember around DC...
on the Eastern half of the Capital Beltway there is the Woodrow Wilson Bridge on the Potomac River crossing when you're travelling on I-95. *AND* there are some huge new flyover/landbridges at the Springfield Interchange(south of DC), where I-95/I-395/I-495 all converge. They're actually not bad once you get on them, but can be intimidating at first glance.
If you come around the western half of the Capital Beltway, there is the American Legion Bridge, but that is a much smaller bridge that the Wilson Bridge.
South of DC there are some smaller bridges, just south of where Route 1 intersects with I-95 near Woodbridge Virginia there is a bridge that is usually called the Occoquan River Bridge, but it might technically have another name.
There's also the James River Bridge.
I think the suspension bridge that ducklite referred to near Richmond is called the Varina (Narrows?) Bridge, but am not sure.
To the OP - bridges really cannot be avoided travelling between NY and Orlando. If your trip will take you down I-95 take a look at a map of the Eastern United States and notice the number of rivers that I-95 crosses, but after Richmond, the number of bridges does seem to decrease. I don't really remember any other major ones, other than the ones ducklite mentioned.
good luck

,
agnes!