I'm a Canon guy myself, they've never failed me.
It really depends on what your wife likes to photograph, if she wants a compact camera there are so many options: The Powershot/Elph series are nice, feature-rich, pocketable point & shoots; the G series have great optics and powerful manual controls, the S series is a nice mix of the two.
You can pick up an older DSLR for that price as well, if she really wants to get into photography.
Outside of the Canon range I'd look at Nikon, Pentax, or Casio. Avoiding anything that relies on proprietary memory card formats like MemoryStick or xD cards.