New school and for non-1st timers: Conservatorium. (The building itself isn't new - but the rooms are a more contemporary design).
Old school and for 1st timers: probably the Grand. Maybe a higher cat. room at the Amstel.
My .02 cents..
EDIT/FYI: worth noting that the Amstel is giving away tickets to the Rijk and the Hermitage for 2 OR free canal ride for 2 on Virtuoso bookings. The latter option - the canals - probably won't be of much use to you, as you're going on a river cruise anyway
