Or also the D90. When I priced up cheapest deals on d5000 with 18-105mm lens, and the d90 with same (kit) lens there was very little difference (30 UKP). That was a few weeks ago. Since then the lowest price on d90 appears to have risen a little, and d5000 dropped so differential may be greater.
d90 adds wireless flash, lcd top panel display,larger/brighter viewfinder, more controls, larger lcd, (and 100g or so) but looses articulating lcd & extra scene modes. Honestly both look great.