It really depends. What you want is a good neutral posture that doesn't put sustained strain on your joints.
Choosing a chair is a matter of fit (size) and fit (the style of chair assists your workflow instead of interfering with it). For example, many people are better off without chair arms. Some work very well using a saddle seat (particular stool variety).
A table is generally a good idea, but it also has to fit. A mouse is generally a good idea - but this should fit your hand and your process - the best choice for someone doing graphics may be very different than someone who is writing a book.