In the very first game I ran, I had the PCs see a lieutenant of the BBEG demanding that a local town pay tribute to her master and swear allegiance. My thought was "Oh, surely the heroes will run off to save these townsfolk from their oppression". I was wrong. Dead wrong. In fact the group looked at me and said "No. She's scary. Lets go hunt pirates!"
Before, or after, your next session there are three questions you need to ask your players.
1) What do you like about the game?
2) What do you not like the game?
3) What would you have me do differently?
If you can get a meaningful conversation out of those three questions, then you can create a great game and group. In fact, I still frequently send that out as Homework in my campaign newsletters. Just remember that a conversation goes both ways so your players have to listen to you too! And if everyone starts talking, pull out a stuffed animal or something. You can't talk unless you're holding it. It may seem silly but its effective.
If you can, try to run the group as mercenaries. Maybe they're just part of a guild of adventurers. Maybe they get hired on to work for the King's army and deal with your mentioned goblin chief. But if shinies is what motivates them, give them shinies. And if they go back on a deal, then you can have army or assassins chase them for a while. This will let you still have a plot other than "Random Dungeon #2346" since you can try to connect the jobs. Who knows, maybe the group will put the pieces together and take the initiative.
If you go the mercenary route then I would highly suggest that at the end of each adventure have the quartermaster or whomever present the PCs with two or three "jobs". Let the party pick one and then prepare it. Yea, it may be a lot of work on you all at once, but I've been there and I know that this will save you more of a headache later on. Besides, I'm sure everyone here will gladly help with ideas.
