...personally, i think the best line of the car is emphasised top-down, windows-up - i keep an arctic silver hardtop on my storm titanium elise, which also helps accentuate that same line a bit, enough so that i've toyed with the notion of having the upper rollbar panels above the window line painted to match...
...my hardtop goes on seasonally when the temperatures climb above 100 or below 30, but otherwise i'm topless as much as possible, even in light rains...