Babyluv personally I don't ind either name although both are quite popular now so your daughter might have a few Siennas in her class (That said my second is an Oliver- common as muck these days).

Just out of interest, the authors of "Freakonomics" suggest that names become "boganised" over time:

In Freakonomics, the authors answer that question by stating that, based on their statistical examination of data, names move through the population from a higher socioeconomic level to a lower level. Levitt and Dubner found "a clear pattern at play: once a name catches on among high-income, highly-educated parents, it starts working its way down the socioeconomic ladder." When the name is adopted "en masse," then "high-end parents begin to abandon it," and the whole cycle repeats itself with a new batch of names.
This site is tracking their predictions in the US : freakonomicswatch