I have Vittoria Randonneur tires with reflective sidewalls. Believe me, you see those puppies from the side!

I wouldn't hesitate to wrap reflective tape on my commutermobile if I were riding her in the dark/dusk.

As it is, she has reflective stickers all over the place. And I kept her spoke reflectors on.

The big hint I've heard is to put a layer of black electrical tape over the frame where you want to wrap reflective tape. Protects your paint and lets you change things later.