Hi Chris,
When I first joined here, my first and most curious question was "why do you people have some many scopes" (as listed on signatures), so I started a thread. The response from everyone is that each telescope does a different job. One for quick grab 'n' go (portablility/small/easy to set up), one for visual (the big one/aka dob), one for photography ($$$$). And of course everyone has got their trusted binocular.
The best advice I could give you is, is to hold off pouring a lot of money like $3000 when you're unsure of what field it is you want to pursue. Astrophotography from what I've come to understand is a money pit, and requires much dedication. I first started out with a 6" dob (apperture + affordability). Within six months I knew what I wanted to do, so I sold my 6" and upgraded to a 10" and I've never looked back. I think it's easier to upgrade up as you progress, than to spend a lot of money that may be wasted. If you want to do both (visual+photography), I think you may be better off going for the dob first (lots of apperture) and then as you learn more, you will have more experience as to what money to pour into astrophotograpy gear with a another dedicated scope.
As for pluses for a dob....
The big plus for dobs (apart from aperture & affordability) is the fact that they take no time to set up. Often a beginners frustration, having to take an hour to set up, then dreaded clouds usually roll in. Beginners (I'd be guilty of it) just want to plonk and look and get a quick wow rush factor. Also, if I only want a quick session (say one hour), I can do that, eliminating set up time. Many people lose motivation with the sheer fact that they have to spend so much time setting up. I have no "go to" on my dob either - I like the challenge of the hunt (it's very rewarding).
My 10" dob just fits in the boot of my Holden Commodore and Mitsubishi Magna, with the base strapped in on the back seat. Big enough, yet, just portable. The tube measures 1200mm. Trust me, you'll get a big wow factor with this. And especially if you are in suburbia and want to see as much as you can, 10" is the way to go.
Find yourself first, enjoy, then go from there. Your money will be well spent then, when the time comes.
