Hi Robert...
Welcome to Aquaria Central, home of the widest diversity of fishkeepers on the internet
Heck of a question, why the possibilities are endless....
If you've done fishless cycling, you already know a little bit about water chemistry, so what are your water conditions. pH? Hardness?
If you've got water in the 6.5 - 7.5 pH and moderate hardness, why not try some southeast Asian fish (since you've got the kuhlie loaches and all). I'd make your mid-level fish the checker barb (one of my favorites...). Very hardy, easy to sex (which is always important to me) in that the males have a dark leading edge on the dorsal fin and the fin is a little redder. Easy to feed, and very subtle colors. Then you could add a single red tailed black shark, just one of the coolest fish there is. It'll grow to about 5 inches long. Once you've had a RTBS, you'll always want one. Then you could add a male betta and a couple of females. Everybody knows how beautiful a male is, but you'll be amazed how beautiful the females are. Add a couple of easy to care for gouramis (gold and blue/three spot are easy to find and hardy) and then when you've got this all under your belt, add a couple of dwarf gouramis. You will have a tank that will knock your socks off, have a lot of movement, beautiful colors, etc.
In the essence of full disclosure, this was my first 55g tank, so I am a little biased. My 55g is currently a cardinal and emperor tetra tank, which is neat, but when a get a bigger tank, say a 150g tank (which won't be until I get a new house) it will be the above tank. I've never seen anything prettier.
Hope this helps,
Val