What Do I Really Need

I'm looking for a windows 8.1 15-17 inch touch business lap top. i5 or i7, atleast 8GB RAM
This is will be a serious multi tasking business desktop replacement workstation. I need insanely crisp multi media multi tasking capabilities with enough memory to store 5years worth of documents for a small business(I could also use many flash drives but wish to have as many accesable files as possible on the desk top.) As I don't plan on upgrading for many years. The primary function of this lap top is clean crisp effortless multi tasking of basic word/excell software simultaneously while Serfing the web and flipping through apps.
What should I be looking for in terms of specs (please give a specific range of specs)
Do I really need a 4th Gen cpu i3 vs i5 vs i7 what do I need & why.
RAM? How much is enough to keep this software running buttery smooth
SSD vs harddrive? Will an ssd suffice alone or do I need a quad core processor to boost productivity or visa versa
bits GHz mhz??????
Help me out here

 

Multiple simple software application running simultaneously with internet, apps, etc. Primary needs: INSANELY FAST MULTITASKING, and the power to support it effortlessly. Please include an ideal list of specs and an estimated over all budget.