I also like Vex a lot- it doesn't look like much in the pan, to me, but once you use it you see there's a reason for it being so popular!
Phloof! is popular, too- I like it as a hilite in the inner corner or as a wash. A lot of folks seem to like Rice Paper, too. Jest, Gleam and Sweetlust are also nice, and can be built up for more color if you wish.
And not to beat the Danse collection to death (since I already raved about Rite of Spring), but Rondelle is also a nice pale color (grey).