Planning out stock for 55 gal, help?

This is a difficult question to answer, since everyone has different tastes. I wouldn't recommend an angelfish to everyone, because these are highly territorial. To safely have an angelfish, the aquarium must have a large surface (in my opinion, horizontal rectangle aquariums are the best), and considering that the angelfish will pick a spot and guard it, you can;t have an aquarium in which the angelfish could pick out a spot that other fish must cross to get to other parts of the aquarium. Tiger barbs are violent fish, especially in schools. Also, they are very quick, so you can't combine them with slow fish. You shouldn't have a problem with the bloodfin tetras or the shark, but i have never combined tiger barbs with Gouramis, so i can't really tell you if there will be conflict between them. As a personal recommendation, I would add an iridescent shark to go with that rainbow, since they will look beautiful together when they both grow to full size. Also, if you're looking for variety, you could consider snails or maybe one of those little water frogs.