Top cases... whatcha got?

[scootercy]

Have a 17' Zuma FX and want a top case to be able to store my helmet, or whatever.  

**Edit, Yahama Case (30ltr) $94, Rack needed $76, and mounting plate for the case $23.  Ordering Thursday.

[aeroxbud]

That seems expensive. I have a kappa/Givi rack with a 30 litre box. It's about as good a quality as you can get. But under £200.
I know at least in Europe, all Yamaha luggage is Givi. Perhaps have a look at the Givi website.