I've been thinking a VROD would make a good second bike. They're fast, way different from a glide, and I see a lot of good low mile used ones in the $8k area.
I don't have that much cash though, so my current second bike is a 73 Honda CL350. I bought it years ago to mess around town on, and it's a good one to loan out to your friends that don't have their own bikes. If someone drops it, no one cries...