I haven't read that many light novels, but I'm very interested in them and there are many untranslated that I wish to read some day (e.g.
Ookami-san and
Daimaou). What I have read so far are the first 2 volumes of
Kaze no Stigma (they stopped translating it
) and a few chapters of
Shounen Onmyouji starting from where the anime left (it's getting translated very slowly). There are a few that already have some translations that I intend to read, such as
Seikai no Senki and
Ghost Hunt. And I do believe there are some
Twelve Kingdoms translations around as well (starting from where the anime left, that is), which I really should read, because the anime is my favourite of all time. Though 12 Kingdoms might not count as a "light" novel series...
To put it simply, I'm mostly interested in light novels that continue from where their anime adaptations stop.