Welcome Steve,
as a 3 week old newbie owner of a 10" dob from andrews commuincations, I can honestly say i have made the right decision. in my signature, i have outlined costs etc of what i have bought and what i intend to buy next. At the moment, there is nothing i have bought that i have regretted. Balance up the comments over the next few weeks and then jump in! I have been looking at galaxies and clusters and jupiter and mars and it blows me and any of my friends away.
This is a guide for what you can see in different conditions
http://astronomy.trilobytes.com.au/m...iterseeing.htm
to get this magnification 400X ie with a 10" dob, i would have to put my 6mm eyepiece in and then use another eyepiece called a barlow to magnify the image x2. at the moment, i can get around 200X.
The main point is to compare the sizes as the aperture gets bigger to give you an idea of what telescope does what as a rough guide.
have fun