Hello Blackhole -

The 10 inch is an excellent choice, with which you will be able to see the following from a reasonably dark site:

1. All of the planets (maybe not Pluto - I have an 11 inch Celestron and I've never bothered to try), the rings and a few moons of Saturn, storm belts and 4 moons of Jupiter, the crescent shape of Venus (when it is on our side of the sun).
2. Great terrain features on the moon.
3. All of the Messier objects (ghostlike nebulae, beautiful star clusters, distant galaxies) - that's 106 deep sky objects.
4. Many deep sky objects that were not seen by Messier - like the Veil Nebula and NGC4565 - a famous edge-on galaxy with a striking dust lane across the nucleus.

I think this a great scope, with the understanding that astrophotography, as mentioned above, is not really an option. Also, be aware that without a clock drive, you will have to continuously move the scope manually to keep objects centered in the field of view (due to the rotation of the earth). So if you are planning on doing classroom demos, you may want to consider a catadioptric or a reflector with an equatorial mount and a clock drive.

Also, if you decide to go bigger, you may have trouble lugging it around and setting it up. So, all in all, I think you are making an excellent choice. Good Luck and Clear Skies!