The canon competitor to the D5000 would be the 500D, both of which could be considere higher-entry level or lower-mid range. The 1000D from canon is an entry level DSLR, whose competitor by nikon would be the D3000. If you look at prices, these pairs should be similarly priced, with maybe a few 1000 dolars between the mid range pair and the entry level pair (depending exactly on the offered lenses as others have said). I would encourage you to push into the D5000/500D option rather than the entry level. Which one you go for, again as others have said, will depend on what sort of photography you do. I chose the canon route personally because they have the 55-250IS for about £200, whereas there wasnt a budget, stabalised lens from nikon in that sort of focal length. So think about what your next lens might be after the body and kit to help you decide.
This is just mirroring some excellent advice i recieved in my 'help me choose a camera thread'.