Hi Petr,
If you are only interested in planetary, and considering your budget - a large goto dob would be my preference. seeing you have mentioned bintel this is what i mean
http://www.bintel.com.au/Telescopes/...oductview.aspx
while you don't need a lot of aperture for the moon, saturn and jupiter come up much better with the extra resolution gained by having a large apperture.
I'd recommend searching for images of planets taken by different scopes and see the results. eg search ED80 Jupiter; then 12" newtonian Jupiter.
BUT if you are planning on doing deep space as well, i'd try and stretch it to atleast a 10" newt which means you'd need an NEQ6 (equatorial) mount (but that would pump up your budget to ~$2600 ish) unless you go second hand.
Best of luck
Rusty