Mostly I use Portra 160 and 400 now. For sentimental reasons I have some Velvia 50 and Provia 400 in stock. Having been given a medium format projector, I want to shoot some 6 * 6 slides to try it out; but for most purposes the Portra is more forgiving and subtle.
I do however have several rolls of Gold 200 which cost about 16p a roll, slightly out of date, but haven't seen any results yet.