I like the look of the Megane, certainly over the Peugeot. But they are very heavy, and the 1.6 is too sluggish. That said, its a city cruiser car, so engine is not important.
However, the mazda mx5 simply HAS to be the one to chose
Theres a relatively new model out, and after all, its the biggest selling convertible in the world since the first day it was sold in the early '90s.
Its a 2 seater, designed to be a 2-seater. all the other we've mentioned were originally 5-door hatchbacks, changed to have a folding roof.
EDIT: p.s. i think i read in the lasst few days in one of the broadsheets that the tin roof mx5 has a lot of road noise, as opposed to the soft-top.