The shark comes with VCarve Pro which is all the software you will need for a while. You can upgrade to Aspire if you need to later.
Be sure to get the Shark Pro Plus HD. You won't be satisfied with a lesser one.
You will need the following (plus bits)
A computer with a USB connection to the control box.
A stand to put the Shark on. Drawers to hold bits and tools are very useful.
A shop vac to clean up the dust.
The following are not absolutely necessary, but I advise them.
A touch plate or a z axis CNC gauge (see Ebay) which is my personal preference.
I like these clamps: http://www.amazon.com/Shop-Fox-D3347-Ca ... =clamp+Fox
Spoil boards. I use 3/8" thick MDF.
T slot bolts are useful to hold things down to the table: http://www.rockler.com/product.cfm?page ... te=ROCKLER
Some type of overhead lighting to light up the work area.
Good judgement comes from experience.
Experience comes from bad judgement.