After HP, What Next?

SFSignal has a list -I just love lists- of sf and fantasy books for different age groups to read after the last HP book is finished.

Their young adult list for sf:

Ender's Game; Card, Orson Scott
Mortal Engines; Reeve, Philip
Tanglewreck; Winterson, Jeanette
Starsiders Trilogy; Gerrold, David (although I couldn't find this referred to as the Starsiders trilogy)
The Hitchhiker's Guide To The Galaxy; Adams, Douglas
Caves Of Steel; Asimov, Isaac
Starship Troopers; Heinlein, Robert
Foundation; Asimov, Isaac
Podkayne Of Mars; Heinlein, Robert
The Supernaturalist; Colfer, Eoin
Maximum Ride; Patterson, James
The Uglies; Westerfeld, Scott
The Martian Chronicles; Bradbury, Ray
I, Robot; Asimov, Isaac
Tunnel In The Sky; Heinlein, Robert
Rendezvous With Rama; Clarke, Arthur C.

Their young adult list for fantasy:

His Dark Materials; Pullman, Philip
Shannara Series; Brooks, Terry
Discworld; Pratchett, Terry
Lord of the Rings; Tolkien, J.R.R.
Young Wizards; Duane, Diane
Pern; McCaffery, Anne
Xanth Series; Anthony, Piers
The Chronicles Of Narnia; Lewis, C.S.
Here There Be Dragons; Owen, James
The Last Unicorn; Beagle, Peter S.
Forests Of The Heart; de Lint, Charles
Magic Kingdom For Sale, Sold!; Brooks, Terry
Bartimeus Trilogy; Stroud, Jonathan
The Dreamhunter's Duet; Knox, Elizabeth
Earth Sea; LeGuin, Ursula K.
Talking to Dragons; Wrede, Patricia C.
Dragonsinger; McCaffery, Anne