Money value:
Skies of Arcadia - Dreamcast PAL
quite expensive
Skies of Arcadia Collector's Edition - Dreamcast Japan
quite rare
Samba De Amigo Box - Dreamcast PAL
rare and expensive
http://www.ebay.de/itm/Dreamcast-Samba-de-Amigo-inkl-Maracas-Matte-mit-OVP-Big-Box-US-NEUWER-/290901943093?pt=PC_Viedeospielzubehör&hash=item43bb1b6335
^and that is NTSC which isn't that rare
Personal value:
Ikaruga - Dreamcast Japan
still sealed