Hmmm.. if her school photography club uses Nikon, it'll be better to get a Nikon. she can use flash and accessories from her school.
All brand produce decent cameras. its up to one's preference when selecting a camera.
Wholesomely agreed, that would be the most sensible thing to do, all in the name of sharing and learning. It is probably why they recommended the D90 - so that you can borrow a great number of lenses and flashes belonging to the club (things that you don't have to spend upfront apart from the body and simple lens). I don't think D5000 would be as versatile and limited choice of lenses that can be fitted to it.
If you chose to be a non-conformist to the club's recommendations, would you lose out in the learning? Unless of course you can afford to buy ALL the lenses and accessories you need on your own... :thumbsup: (yup, very cost saving indeed!)