Does not work yet January 2010 in Ubuntu 9.10 64-bit or Sabayon 5.0 64-bit. Windows 7 64-bit and XP 32-bit works fine.
Fast, compact and low power consumption video card. 2 * DVI + HDMI + DisplyPort, ~ 130 €.
http://www.amd.com/us/products/desktop/graphics/ati-radeon-hd-5000/hd-5750/Pages/ati-radeon-hd-5750-overview.aspx
Update: feb 2010: driver downloaded directly fron ATI works 90 % in Ubuntu 9.10-64 with dual monitors.