Hi Quack
you'll need to look at a combination of aperature/budget/portablility - and it may not be in that order.
the bigger the aperaure - the more light - the more deeps space object you'll end up seeing but then portability may be the issue.
going a Dob is a good way to start off - did the same myself - and from reading all the other posts about first scopes it alwys seems to be dobs, dobs, dobs (plus binos)
cheers
Martin