I'll throw out a suggestion since you are still in the planning stage that would come to my mind if I were planning a 55 Gallon.
55 Gallon:
Hatchet Tetra School (5-10)
Rummy Nose Tetra School (10)
Harlequin Rasbora School (10)
Amano Shrimp
Corydoras (5) or a Hoplo Catfish
Bushy Nose Plecostomus Pair or Otocinclus Catfish (5-10)
Bolivian Ram Pair, German Blue Ram (Male + harem), Kribensis Pair
Plants: Vals, Hygrophila, Crypts, Java fern
The fish I suggested use good space of the tank dimensions, with some bottom dwellers, some mid level, and some top swimmers. 55 Gallons are tall, so I've suggested some forgiving plants, and some low light plants. I like to keep community tanks fairly full. Just stock it nice and slow and buy juvenile fish to grow out. All the plants I've slited I'm sure you can find someone who would be willing to give you enough to seed your tank after they do a trimming of theirs.
If Kribensis are kept, use Otto Cats instead of Bristlenose Plecos and Corydoras instead of Hoplo Cats, as they will have confrontations over cave space with the Kribs. Both or all could be kept, but the decore in the tank would need to satisfy everyones need for cavespace.