i like a group of works from one artist.
its like a little teaser of what they ahve to offer and if i like it i look at their gallery, i like their gallery and their tastes i look at their favourites =]
i love all your features, but it's great when you choose a load of pics by different artists on a similar theme. you seem to be really good at both chosing a theme and choosing pics to feature in the theme.
single pics are good, but if it's not one i'm fussed on, i'm less likely to go and comment/look at the artist. with many thumbs, there's always more than one that will get a good look.