It's great that you are thinking of getting into astrophotography. As you know the sky's the limit
when it comes to cost but you can also get fine results on a budget. Your equipment list is a good starting point. Having a dual axis motor drive is a slight luxury as for most work only the polar axis needs to be driven to counter the Earth's rotation. However, the cost of adding that second drive motor is pretty small and it's nice to have.
The issue of refracting telescopes (where the optics are lenses) versus reflecting telescopes (where the main light gatherer is a mirror) is a bit more complex. Refracting telescopes are pretty low maintenance but reflecting telescopes are, everything else being equal, cheaper for a given light gathering power. I prefer refractors for casual use but if I wanted to get into serious deep sky work then an 8"/20cm or larger reflector would be my instrument of choice. As for focal length and focal ratio, with a modest budget choice is pretty limited. If you intend to shoot the Moon at a telescope's prime focus then a focal length of at least 500mm is good to have. Bear in mind that you can add a Barlow lens (or equivalent) to the eyepiece end of the telescope to magnify the image on your camera's sensor so shorter focal lengths aren't a real deal breaker. An objective of 70mm diameter or greater is enough to get started but, unfortunately, bigger is usually better.
If you are just starting astrophotography then specialised filters aren't a priority. You must
use such a filter (in front of the telescope) for solar observations because viewing the Sun through a telescope without such a filter is a great way to lose your eyesight. Doesn't do the camera much good either! I note you are a Nikon owner: be sure to read my post here
if the Nikon automatic noise reduction needs to be stopped with your camera. On another tack, don't forget that webcams have been used with great success at the end of telescopes and have the advantage of being relatively cheap.
There is a huge depth of information on the Net about astrophotography so here are a few links to get you started:
Astropix - This site is a great resource. In particular, it has an excellent Astrophotography Techniques page with lots of advice on choosing telescopes, mounts, cameras and much else.
Sky & Telescope - There are some useful starter articles on astrophotography as well as guides on choosing equipment and a wide selection of articles and news items.
Astro Adventure - A fun site with some videos (watch out Gordon) and a few introductory articles.
Adventures With High Resolution Webcam Lunar Mosaics - Webcam astrophotography is a big subject in its own right. This article shows why and includes some astonishing images.
On a lighter note, the
astronomical icon here in the U.K. is a gentleman called Patrick Moore. As well as being the author of many books and being responsible for getting generations of youngsters enthused about astronomy he has also been presenter since day one of the Sky at Night which is the BBC's longest running series, now in its fiftieth year. Visit the Sky at Night site
and you can watch
some of the episodes online (hopefully this link works for browsers outside the UK).
I hope the above has been useful. For all budding astronomers and astrophotographers I also strongly recommend getting in touch with a local astronomy club. If the club is any good then it should welcome the opportunity to introduce newcomers to the hobby and it should provide a great resource of information specific to your own country.