I change the oil on my 07 LX FWD with 35,000 miles every 5k with synthetic blend. After 3k or so the oil looks pretty dirty. My Ford Focus gets oil changes less frequently and the oil always looks new. I live in L.A. and do mostly freeway driving. I've never had a car that the oil looked so dirty so quickly.
Its all that smog down that thar hill.:grin: Mine after 5000 is a little dirty witch is normal. If you are doing more city driving it will get a little darker or if there is a blowby issue it will also.