Somehow I missed this thread the first go-'round. I made an impulse purchase to get a Ninebot (Segway) Mini for ~$300, and it's a ton of fun. The problem I have with it is that you very quickly get comfortable traveling at the max speed of 10 MPH and wish it would go faster.
An electric unicycle (EUC) is on my purchase list. There are ones that will do something like 45 MPH and have a 45 mile range. I probably wouldn't ride at those speeds without full leathers and a helmet, but it would be fun to have the oomf on tap. They are silly expensive though, so I'll have to keep an eye out for a sale or a good price on a used one.