For me, the most important thing is you have got to like the miniature you are painting.
This may sound odd, but I find it is true. I painted Sonnia and Seamus real nice first go, but the ortegas I have started and stripped several times. They just don't feel right. I only got them because I play guild regularly and wanted the options to field them but i don't like the models as much as the others and I think this subconsciously affects my painting.
It also explains why I have lots of armies for warhammer, 40K, confrontation, hordes, warmachine, ancient romans, samurai and napoleonics all with a mass of primed metal and a couple of very well painted figures!