What is the best image editing software?

Price is not a consideration. A certain wealthy friend of mine who forgot my birthday will be told that I want this software for my present.

[Last year I asked for a lightweight sweater (called a jumper in Australia) and she produced a $AU 600 Kashmir sweater.]

Some of the features which I especially require are:

1. The percentage size of the image so that I know how much to reduce it — without hassling with calculating pixels.

2. The ability to significantly reduce the size of the image without distortion.

3. The ability to read any type of image e.g. gif, jpg, bmp and so forth.

4. Will work preferably on Win 98x and upwards, but XP is OK if necessary.