Growing Citrus can be tricky as they like lots of light, feeding well in the growing season but dont like to be kept wet, but they are tough and even very poorly specimens can be revived.
Lemons and Oranges are great to grow purely for scent and the odd fruit but my favorite is Kaffir Lime as its an essential  ingredient in Thai cooking and almost Impossible to buy fresh and the fresh leaves add so much more to a dish when used.