What a great thread idea!
My 30g is a very KISS setup with a pair of maroons and a few inverts - it has some pest anemones and microalgaes, but they kind of fit the tank's theme (everything in the tank was unwanted or rejected by someone).
The 90g is a tad more automated and it too has its imperfections (a little turf algae, Halimeda growing like mad everywhere and a few pest nems) but overall it's a gorgeous, very healthy tank.
I guess I'm pretty easy to please; as long as the water stays in the tanks and not on my carpet and the livestock is healthy, I can't complain
