Advice? Get familiar with the locations of all the gas stations in your area. You now own what is maybe BMW's least efficient V8 ever. But they are cheap now so it doesn't matter that much in overall cost of ownership. Congrats and have fun!
2011 X5M (coming next week!)
2008 X5 4.8i Space Gray/Tobacco, Premium, Sport (includes AD), Active Steering, HUD, Tech, Comfort, Cold, Climate Package, 3rd Row, Prem Audio, running boards, OEM hitch
2005 X5 4.8is Imola Red, Nav, Nappa, Comfort seats, OEM hitch
2004 X5 4.4i Sport (sold)
2004 X3 3.0i 6MT (sold)
2002 M5 (sold)