I'm going to say this before Ninjouzata gets a chance - for the 10G, 2 pairs of Peacock Gudgeon (aka Peacock Goby). Provide plenty of small caves (I use shortish lengths of ½" plastic pipe, the kind used for water plumbing), and you may well get them breeding. You could add a few male endlers for a bit of variety, or some amano shrimp - I wouldn't recommend any of the smaller shrimp species, as my Peacock Gudgeons thought the Cherry Shrimp were lunch.
For the 30Gallon, I'd recommend a trio (1M 2F) of one of the smaller apistogramma species. My personal favourite is A. Agassizii, although A. Hongsloi and A. Cacatuoides are also stunning. Then have a large shoal of a smallish barb/tetra/rasbora species. I have a similar sized tank which has Cherry Barbs, Pentazona Barbs and Cardinal Tetras, but you can also have any of the species that Wills suggests too (remember that Galaxy Rasbora have been rename Celestial Pearl Danio). You could also do 2 smaller shoals, especially if one of these is one of those micro species. Finish off with a group of 6 of the smaller cory species, Pandas are ideal, but also look at Salt & Pepper Cory (not to be confused with Peppered Cory).