I love Puppia.
I think they're my favorite harnesses EVER. I've tried others and always go back to Puppia. They're lightweight (it's a mesh material), easy to wash, comfortable, come in different colors, and easy to take on/off, etc (most are plain -- which I actually like, nothing too extravagant).
Amazon.com: Puppia Soft Dog Harness (Mesh) Orange... They have the regular vest-type that just goes over the head, but they also have step-in's.
My second favorite is chattiesmom harnesses! They are really lightweight, custom fit, and the colors are really vibrant and nice. I like them alot.