ID usage question

I've been trying to make sense of the ID field and hope someone could straighten me out.

Simple process:

Input information into Form_A

ID record is populated in View_A

Ok, that's easy enough to understand

Now, where my question lies is how to get View_A.ID to follow a record through several forms?

Technically, I'll be using a UNIQUE IDENTIFIER, in my case "Opportunity_Title". This field will be referenced in every form beyond Form_A as a it steps through each stage of the process.

As each Form_n+1 progresses, I need a report and I need an aggregated report based on "Opportunity_Title".

So, do I need the ID field - or - am I setting myself up OK using "Opportunity_Title" as my UNIQUE IDENTIFIER?

I was dabbling w/ the Functional URLs using the ID created in View_A, but then today I looked and View_B.ID is a different number - silly me. So, now I think instead of calling ID in my Functional URL, I'd actually call "Opportunity_Title".

Summary - I have 2 goals

Goal 1 - Determine if my UNIQUE IDENTIFIER should be "Opportunity_Title", or, how to have the ID created in View_A be it.

Goal 2 - Views based on Functional URL that will allow me to create a comprehensive view of View_n+1 based on my UNIQUE IDENTIFIER from Goal 1.

I hope that makes a lick of sense.

Thanks,

Scott