If you have a large shoal of tiger barbs - 8 plus - they are much more interested in chasing each other than other tankmates. LOL But yes, you would need other fish that will hold their own with tigers. I actually have juvi tigers and angels in my 3 ft tank (moving them to a 5ft soon) and there aren't any probs. Both fish need to be in decent groups, IME. Perhaps a larger gourami - but it all really depends on the individual fish. Some will get along, some won't. Fickle devils!
Angels are actually quite hardy, as long as the water is soft and slightly acidic. But they really do need to be in a group of 5-6, unless you have a breeding pair. Angels are cichlids, so they can get aggressive. They are also territorial.
For bottom feeders, cory's are great - they are entertaining, sweet and funny! BUT, your tank MUST be well established. They will not cope with a new tank. They can be really sensitive to nitrates, so keep them down. You need to keep 4-5 of them - they are shoaling fish as well. Bristlenose, on the other hand, are quite happy on their own.
For a centrepiece fish, have you looked into south american cichlids? A lot of them are beautiful (look at angels!) but peaceful - compared to their african cousins, anyway! Blue Acara's are beautiful - and hardy. They get to about 8in. And they can hold their own against tiger barbs. Or even convicts (which are actually central american) could work well.
Sorry for the long post! I get a bit carried away. LOL
Good luck!!!
Carls