The next thing I would do is get a Nikkor 50mm 1.8 lens. Do not cheap out on the lens! These will last you a lifetime, and the lens is the most important part of the process. A cheap third-party lens on a $2,000 camera makes that camera look like a cheap starter. A sharp Nikkor on an old body like the N65/55 will put out amazingly good quality pictures.
I recommend the 50mm for three reasons. One it is one of the sharpest lenses on the planet; two, it is light and relatively cheap; and three, it is good for learning on.
For around $200 you can have a complete starter system (with no flash) that will last you years. Good photographers know the fancy cameras are for the fancy shots. They don't take better pictures, they just take better pictures of the way drops of water fall off of a duck rising out of a pond. You'd have to be an awfully fast gun to get that shot on manual, but with the F5 you can get it and then the duck's friend, too.
In my opinion, by the time you are ready for an upgrade, you'll want to go digital SLR. In the meantime get the above system, and expand your arsenal of glass before worrying about fancier bodies.
And have fun!