Well, first off, there are lots of threads on the scent of these candles already. But ignoring that, I think it's really up to your preference in smell.
In my experience, all the scents are fairly high quality, so it just depends on what you like. I personally favor the Dark Vanilla and Bourbon scents. My good friend prefers the Water Cucumber, while it is totally not for me. Some people love the Truffle Gardenia, but it's comparatively very floral. I would really like to try the Vetiver Honey in the ember series.
My recommendation would be to go with what is most similar to your usual favorite scent. Sweet edibles? Masculine spices? Flowers? Citrus? Or you could always try the sampler. More expensive but awesome