i recently got a 5d mark II with a 24-105mm lens - dont get me wrong its frickin sweeeet accept in comparison to my 550d kit lens 18-55mm its not as sharp which is a little disapointing. the 550d kit lens was also good for close up shots and with a flash at f7.1 or f11 you could get some very sharp results
basically im looking for something similiar for the 5d mark II - not as wide as 24mm but with the macro capabilities but not a dedicated macro lens - i already have the 100mm macro anyway but i need something thats a bit more everyday and not dedicated to one subject - thats why i loved the 18-55mm - i could wonder around taking scenic pics but at the same time if i spotted a crab or a mushroom or whatever i could get close and capture lots of detail