ExploderWizard
Hero
How about you lead off with a couple of wolves in what seems to be just hungry predators. It's dark and with only the firelight to see by, it's not until a couple rounds into the fight that they get a chance to make a Perception check to notice...the wolves have collars!
An instant later a goblin arrow zips out of the darkness at them as the pair of dismounted wolf-riders attack! Given a chance, one of the goblins will dart into the camp and grab one of their backpacks and run away. If the wolves are still alive then the goblins can whistle for them and then ride off into the night.
This encounter would establish several things:
There are wolves around here.
The goblins use them as mounts.
The goblins are bandits and raiders who are more than willing to attack even heavily armed groups travelling on the roads.
And those goblins probably have a lair around here somewhere...
OK this encounter has "winner" written all over it.

Party makeup will be a big factor in what types of monsters to use. I would try and find out what classes the PC's are as soon as you can. The same encounter can be a breeze for one group and a boring slugfest that never ends for others. Post again when you know the character classes and I'm sure you can get very specific help.