Since you love gouramis, I'd recommend Pearl Gouramis. I have 3 in my 55g tank, they're very pretty. Male is has bright orange all across his underside. I'm not a fan of tetras, but I have a school of 8 Bloodfin Tetras that look very nice in the tank. They add al ot of color to the upper levels and are very active. I love the look of marble and royal plecos- They would be a good choice for a flashy bottom feeder. Dwarf cichlids are also very colorful, and love plants. A pair of Kribnesis would look nice, and they have a high potential of breeding. I have a group of German Blues/Electric Blues in my tank with the gouramis. They're very bright and very smart fish. A pair of altum angels would also look nice with a smaller school of barbs. Cherry or Tiger. All depends on personal preference. Good luck!