The Nikon D90 is a good Digital SLR and I have to say I'm satisfied with the picture quality, feel/weight of the camera and the way the function buttons are layed out. The only problem I have with the camera is the error mesages. Two appear intermittantly. "F--" is the least severe as all it takes to free that is a little twist to the lens as this will make good the contacts between the lens contacts and camera's contact ring. The other "Err" code that appears, again intermittantly with no warning can only be freed by removing and re-installing the battery.The camera completly locks-up and won't turn off from the switch. There are reports of users having to do this a few times but once always cures the problem for me. I'm very disapointed with Nikon as this really is the achilles heel of a very good camera. I purchaed the camera a week ago with the 18-105 kit lens and this has occured at leats 6 times. I'm taking it back to Jessops today to get a full refund. I'll have no problems buying the D90 again but only once this problem has been sorted. If your happy to remove the bettery in the middle of shooting or to give the lens a little twist to cure either, then I can't think of anything else that would deter you from buying it.
05/02/2010 D90 Update.
OK. I bit the bullet and decided to purchase another D90 with kit 18-105vr lens a month later. I'm pleased to say I've had it for several months now and used it extensively without a single error code appearing. No locks up's or any other problems. Sounds to me Nikon have/had some quality issues. Purchase from a supplier with a good returns policy who will allow you to return the camera if faulty and repurchase with no problems . 5 stars for my 2nd and new D90.