Hi Rebecca,
while a dobsonian reflector is an obvious choice, I think your two options of Maksutov Cassegrain or Maksutov Newtonian are also worthy contenders for a few reasons.
they're compact with their folded optics (Mak-Cass), mostly goto so easier to find objects although you won't learn star hopping that way, usually longer FL I think so good for planetary observation.
I'm not an expert so i'm sure others will correct me if i'm wrong.
I guess the biggest factor would be how portable do you need it to be?
collapsible go to dobs are good value for money, but a 12" is quite heavy.
some common questions, would you be transporting it often or more from your backyard?
8" is a good size whatever type of reflector it is and with your budget, you should get a decent one.
you'll also have to keep a bit aside for some decent eyepieces.
a 25mm and a 9mm 2" would be ideal.
did you already have a few scopes in mind amongst the mak-cas or mak-newt?
found this in a search
http://www.stellaroptical.com/diff-summary.htm