I wouldn't put barbs in a 10 gallon with gouramis. I think you would see a lot of fin nipping and fighting. Gouramis can be quite aggressive themselves, and a 10 gallon is really minimal when it comes to tank sizes. 6 tiger barbs would be an interesting choice or your cherry barbs would be good also. You would get to see some of the schooling behavior, and they would be very active in your tank.
When Gouramis are enclosed in a small space they tend to fight and something will die and a 10G tank is a small space for 2-3 even dwarfs. That was one of the mistakes I made as a newbie and it was really sad.
Je55*e - the guppies and corys are a good suggestion but the hatchet fish need to be in groups with lots of room to swim lenghtwise. They tend to "fly" out and become carpet critters in a short tank.
A group of Cherry Barbs alone with lots of plants would be stunning. With plants to hide in they tend not to be as nippy.
Hope that helps
I agree with Stradius and Carol.........Cherry Barbs are a very peaceful fish. I have never seen my even attempt to nip, and they are probably my favorite species in my community tank. I wish I could get 2-3 more to create a bigger school for them, but I don't want to push the limit of my tank. A bright red Cherry Barb in a tank with green plants and say blue/green gravel makes a very beautiful color contrast, and you can always find them in the tank easily. (Unless they are hanging out in the plants, which they do quite often.)
Upon further review.....maybe my cherry barbs aren't all that peaceful after all. They have seem to have been nipping at my guppies fins at night when the gupps are sleeping. After putting them in a 'time-out' tank, even my bloodfin tetras became more active and were swimming all over. Before they would just hide in a plant. It seems the much smaller cherry barbs were the bullies in my tank. :;sm