We have a number of succulents and cacti which seem to do quite well on the sunny side of the balcony:
  1. Ceropegia woodii (string of hearts fine)
  2. Crassula ovata c.v. 'Gollum' or c.v. 'Hobbit'
  3. ?Euphorbia antiquorum?
  4. Fockea edulis
  5. Haworthia truncata
  6. Lithops (various, some grown from seed)
  7. Portulacaria afra (spekboom)
  8. Titanopsis calcarea

(to be continued...)
Also some plants in these genera (perhaps?) which I have not yet figured out a species for. 
Echevaria spp?
Faucaria spp (tiger jaw)
Gasteria spp
Haworthia spp
Pleiospilus? spp
Sedum spp?
Some of the succulents.