Either 1m 1f dwarfs, 1m 2f dwarfs, 1m 3f honey or 6-10 (1-2m) sparkling gouramis would be my choice. It's not just dwarfs who may have temperament problems, it depends on individuals with all of the species. There are also a number of rarer species which are very peaceful, but difficult to get hold of.
I'm glad i cam across this, saves me starting a thread...
I took some time in deciding which Gourami to have for my 110L, 3 foot tank and finally went with Dwarf Gourami, 1 male and 1 female. I went with this decision by what i read on this site and continuous advice from my local M.A store... and i'm pleased i did ! They have been in 48 hours now and are slowly (but surely) exploring what's around them.
I also read, with some concern, the amount of problems keepers do have with these fish... with one factor always coming up, bad water parameters. I feel i am proud enough in keeping my water clean and fresh enough to accomodate these fish, another thing that was pointed out to me at my L.F.S. I also got given a great little tip regarding these fish.. cover the tank as much as you can (i used my 2 fish tank beach towels) for 8-12 hours once they first go into your tank, these fish are very mellow and very easily spooked..they seem to be very thankful for it.
Unfortunately, i can't comment on any other Gourami species, but as KK mentioned, if it comes down to availability then go for the Dwarf.. i shall be posting a latest tank pic soon, with it being relatively new, i hope to remember to include a link to you so you can get a little feel as to how they may look in your tank.
regards,
Terry.