I started with a Vento Zip R3i to see if I'd like scootering.
About $1200 new.
I fell in love with it--it was MUCH more fun than I thought I'd have with a 50cc bike. About a 37mph cruise, 43mph top end, 75-80mpg, stone-reliable, and great brakes. I wouldn't hestitate to buy another Vento.
We ended up buying 2 more scoots: a nice Kymco Super9 and a Stella.
Either one is great as practical everyday transportation where I live.
My Stella with a Pinasco 177 kit, Jim Lomas/SIP expansion chamber, and Dellorto 24G carb will cruise at 55-60, with a top end somewhere just north of 70, and will accelerate briskly getting there. Plus I can easily pull from a stop in 2nd, and from a rolling stop in 3rd. It will idle around town in 3rd like it's an automatic.
I got the Stella because of the history and aesthetics of a Vespa PX 2 stroke 150 with manual transmission. It's extremely durable and suited to hard everyday use as a commuter, but it also works well for scooter touring. Parts are cheap and plentiful, and making it go faster is easy and cheap.
About $3000 new; $1900-$2500 used.
The Kymco Super 9 is a solid bike that handles great, and is a great race platform. It's not a cheap scooter, but Kymco puts a 2 year warranty on it, and it's built more like a motorcycle than a scooter--great lighting, stiff chassis, nice tires, excellent fit-and-finish throughout, dual disc brakes, liquid cooled, full instrumentation, and plenty of hi performance upgrades available.
About $2600-$2800 new.
Adding a scooter (or two) to the motorcycle stable has been a great decision. They're cheap to own and operate, and much MUCH more fun than I ever anticipated they'd be. I can either cruise around at a relaxed pace and just enjoy the scenery that used to be blurred, or go drag the centerstand in tight turns.