I'm a beginner myself, but here's my experience. First of all, as the saying goes, the best telescope is the one you have with you. That is to say, if you need to move the telescope at all, think seriously about portability.
My first scope was a 6" dobsonian that I bought on craiglist for $120. It was a great first experience, because I was able to see some amazing things. But it's size was a big downside. I couldn't fit it and a passenger in my civic coupe. It was also so heavy that I often didn't feel like taking it outside. If you're already in a dark place and can store it somewhere that's easy to get to, then I think it'd be great. If that doesn't apply, I'd try for something smaller.
I've recently been thinking about getting an Orion StarBlast 4.5 inch dobsonian, or ST130 (though this requires a mount). They're inexpensive and portable. Not nearly as much power as a 6 or 8 inch, but the portability trade off is worth it for me.
One other side note: if you get something with a tripod, it's gotta be at least decent. I also have a ST80 telescope, which I wouldn't really recommend it this case. But it has taught me how important the tripod/mount are. The tripod that came with the scope was unusable. I got really frustrated on forums, because so many recommendations were for $700 tripods, specifically to use with this $100 telescope. I've been happy enough with an $80 Orion Tritech II; it isn't great, but it isn't $700 ;)
Guilty as charged - my personal favorite setup is a $150 tube (Celestron C90 Maksutov-Cassegrain) on a $700+ tripod and mount. I wouldn't recommend it to a beginner.
6" f/8 newtonians like the typical 6" dob are really at a sweet spot of aperture, size, optical quality, and cost. They've been the classic beginner's telescope for generations for a reason. I wish I'd had one on a pier-mounted equatorial when I lived under dark skies.
If you are unsatisfied with the f/5 ST80 I don't know if you'd be happy with another fast (low focal ratio) telescope. See if you can find someone local to you to let you look through a telescope similar to the ones you're thinking about.
Good point that another fast telescope may not be what I'm looking for. Though I definitely still need to play with the ST80 more before looking for something else. I think it may have just compared poorly to the 6" Newtonian (not too surprising).
It's interesting to learn just how important tripod and mount are. I think the frustrating thing for a beginner is that they really just need a setup that works, whereas experienced users often describe really finely tuned expensive setups. And to the beginner it can sound like this is the only option.
My first scope was a 6" dobsonian that I bought on craiglist for $120. It was a great first experience, because I was able to see some amazing things. But it's size was a big downside. I couldn't fit it and a passenger in my civic coupe. It was also so heavy that I often didn't feel like taking it outside. If you're already in a dark place and can store it somewhere that's easy to get to, then I think it'd be great. If that doesn't apply, I'd try for something smaller.
I've recently been thinking about getting an Orion StarBlast 4.5 inch dobsonian, or ST130 (though this requires a mount). They're inexpensive and portable. Not nearly as much power as a 6 or 8 inch, but the portability trade off is worth it for me.
One other side note: if you get something with a tripod, it's gotta be at least decent. I also have a ST80 telescope, which I wouldn't really recommend it this case. But it has taught me how important the tripod/mount are. The tripod that came with the scope was unusable. I got really frustrated on forums, because so many recommendations were for $700 tripods, specifically to use with this $100 telescope. I've been happy enough with an $80 Orion Tritech II; it isn't great, but it isn't $700 ;)