The Piaggio MP3 scooter has two wheels in front and one in back. There are three sizes (250cc, 400cc and 500cc). The two front wheel adjust to let you lean into curves. My friend has the 400 and really likes it.
This is obviously much larger and heavier that a typical scooter (such as a two wheel Vespa). One of the interesting features is that the two front wheels can be set to lock when stopping to provide three points of stability (so you don't need to put your feet down to hold it up when stopped). The MP3 has an automatic transmission.
It can easily go highway speeds – to do so it is probably best to have the optional full windscreen or a full faced helmet. It gets about 60 miles per gallon and has 3.2 gallon tank.
There is some storage under the seat (for the helmet when parked, or a bag of groceries on the way home. There are also some optional storage cases which mount on the back.