Is the Nikon D40 still worth buying in 2010?

I am going to be taking an introductory photography cl in the spring and am looking to purchase a DSLR camera, preferably in the five to six hundred dollar range. I am interested in street, portrait, and landscape photography and would like a camera that I can grow with for a few years as I consider photography as a career. I have done research on many DSLRs and have read good reviews on the Nikon D5000 and stellar reviews on the Nikon D40. My question is this: Is the Nikon D40 still worth buying today, especially since I can get a brand new camera for a little more than a used D40? I realize that newer is not always better, but for those of you who own the D40 and love it, what do you love about it, is it a camera that will last me at least a few years, and what are your reasons for not upgrading? Thanks so much.