My 46 is a Tanganyika tank. Some Julies and brichardis would be nice, You can throw in some Nice Altolamps that will REALLY top things off. If you want some nice color look into the Cyprochromis species, the leptosomas are amazing. If he is looking for more color then I would go for Malawi setup, Some nice Alonocara and Hap species would make a wonderful show tank!