They should keep going , with a Psycho Barbie next. And maybe a Rear Window Ken.
Here's the product page: http://www.barbiecollector.com/shop/product.aspx?sku=L9633
As far as stuff you need to get though, this should shoot up towards the top of your list.
NEED MORE KIRBY. And seriously, it's worth the $49.99. Beautifully designed HC, fantastic story, and great extras like the original penciled pages.