my 20D body+lens is the std. lense +body combo... the 18-55mm is a 3x zoom...
you have to remember, that you can buy multiple lenses... i dont recomend the sigma, or quantaray 100-300mm lens
it is far cheaper to buy the body alone, you may want to get something thats a 50-200mm lens or so... they have good zoom capabilities, while having a decent wide-angle ability.... also it would mean you may not have to change your lens as often... so you have less opertunity to let dust in it, or the CCD.
things you definately need...
CPL...if you only get one filter, thats the one to get
a tripod... perfect for high-zoom stability, and night shots
a 1gb compact flash card... if you can afford it, id recomend the highest speed card.
a decent flash is an eventual must... as the flash it comes with is only goof for about 6-8ft effectively.
a microfibre cloth for cleaning the lens
oh, a camera bag is a good idea too
also... its fewer MP..... but i hear great things about the Nikkon D70S' quality