Something else to watch out for.....look out for the way megapixel specifications are produced by the manufacturers. There is a tendancy to quoute a higher than what is actualy true figure, which is based on pixel interopolation or something, as well as the actual number of pixels, which is the more representative figure. Often you will see 2 figures qouted, such as an "effective pixels and tru pixels".
Often the difference can be as much as twice as much. A camera can claim "6 million effective, 3 million actual".
Its a little bit of a con, as its the lower figure thats the important one, but often the higher figure will be the one thats touted, with the smaller figure either in very small print, or not printed atall. The cheaper supermarket cameras with no optical zoom are often advertised in this way, and its something to watch for. It doesnt mean a camera is a bad one, but if you were comparing a true 3megapixel against a 6megapixel efective but 3 true, dont thing one is twice as good as the other.
I would go along with the rest of the advice you have been given, namely that optical zoom is VERY important, and digital zoom is not....and at least 2 megapixel really is required. I wouldnt agree on Lithium Ion batteries though, you can get NimH 2300Mah rechargables very cheaply these days that will last ages.....most digital cameras arent as power hungry as they used to be.