Must have Mac software

[spudbynight]

For someone considering moving from a windows based PC to a Mac what are the must have bits of software on the Mac?

What will I miss from Windows and what are the best replacements?

 

[spudbynight]

I have a load of pictures that I want to sort and perform some minor corrections on.

Will iPhoto be enough to do all that?

 

[spudbynight]

Thats about as much as I want to do.

Really want to be able to tag and organise them efficiently as well.