Themed Gear
off the top of my head:
heritage armor
ascalonian catacombs set
human cultural tier 2 armor
forgot masquerade crafted set
(edited by Lumpy.8760)
I would recommend the masquerade set as well, and I also think that the Exalted crafted set can look pretty good. Ultimately though, I think that most of the light armor available can suit a mesmer rather well with the proper color scheme and weapons to tie the look together.