IMO, 16's are a good balance between looks and not-slowing-your-sh*t-down-too-much-ness. At least for Civics.

 

yeah, i like 16s too, because tires arent as expensive as for 17s, and you can get some good performance sizes for them, but you dont have much to choose from in 15s. 50 series is about the lowest profile you can find in 15s.