Ok, here I'm going to sound just totally "noobish" but I guess I've never really understood what people really meant about "hi-tech" vs. "lo-tech"... where's the line, really?
I guess... 1 - do you have filtration? what kind? a heater? I would put like... 8 angelfish in a tank like yours, toss in some guppies and call it done! (that's because I just did nearly that with a 45 that I'm wishing I could post pictures of...)
really, though... you could toss in 60 neon tetras... or 10 female bettas... or.. maybe 5 or 6 discus... or... 1 arowana (until he gets too big) or 2 goldfish (probably not goldfish)... or..
How chock fulla java fern and moss is your tank? covered from head to toe?
honestly, though, you've got a LOT of play with fish here.
! oh, just noticed you said you were gonna put shrimp in it... Maybe you'll wanna check into some gouramis of some kind? Dwarfs are colorful... sparkling are prized... Chocolate gouramis are apparently really difficult to acclimate - though I think that's mostly if you have to order them. A store near me had a few in stock last time I was there. I'd have bought them if I wanted some.

but I don't! so...
yeah, it's up to you, man.

This is probably one of the more interesting aspects of aquarium keeping... making the choices.