The Mavic Open Sport rim is another good choice for those on a budget. I got those with Formula hubs and Sapim spokes on my wife's SS.

Velocity Aerohead rim is much stronger than the older Aero rim.

For those that want to keep 27" wheels on their older conversions, Sun and Velocity make great rims in that size. The Sun CR-18's are very shiny, a good retro look.