Some questions from a newbie

I am 95% likely to buy an iMac in the next refresh.

One thing I want to do is manage my photos. I have a load of them all over the place. I want to pull them together and tag them properly. I also want to perform some minor corrections. Now, I will be running the Mac on a Windows network with the photos stored on a server. Will iPhoto do everything I want and will it manage the photos in such a way that other devices can view them?

My wife has expressed an interest in getting into photography as a hobby. She has a good eye and so I am thinking of buying her an entry level SLR or similar. Is doing that should I look at getting something like Aperture?

For managing photos you can easily use iPhoto, although you would need to make it point to a server storage rather than locally on your Mac. IUf you find that iPhoto is not your cup of tea, then Google's Picassa is a good alternative.

But as you say, for photography at home then Aperture would be a better bet.

AS for file formats there is no special format that iPhoto uses that is not that PC users cannot access