I currently have 95k on my 04 3.0i. Have really only done regular maintenance and front end suspension service on mine so I'd say I've been blessed. I can only imagine what changing all the rest of the suspension bushings will cost me once they all wear out.

From 100k on, the only things I would be looking to have serviced or replaced are front/rear suspension and subframe bushings, all struts on your x5, transmission fluid/filter, and ball joints. Those can get costly, but wont be so severe if you catch them in time.