It really is tricky. people have different tastes and styles. Some people ( i have thought about it too) would stick an oscar and a couple of other fish in that tank, but they are most definately not community.
I can only really tell you what i have in my community:
Bosemani Rainbows (but you knew that )
Panda Cory's - love 'em
BN Plec + couple of otos
Cardian Tetras
Black Phantom Tetras
Pentazona Barbs - nice peaceful barbs.
i know joecoral says £5-10 a pair round where he lives but i spent £23 on my pair, as after alot of searching i could only find them in one store. i know they were expensive but well worth it
sevrems or parrot fish grow to a good size and are very colourful. i have a pair of gold sevrems and a pair of red blooded parrot fish and they blow you away. also they are not to expensive so you wont break the bank