Clarification on Apple ID and @me.com addresses please.

Before I post this, I have spent hours trying to find a definitive answer and have failed, so here goes.

I had an Apple Id, which was my email address prior to using an iPad, let's say *...*@gmail.com, and that is my iTunes sign in.

When I upgraded to iOS5, I was asked to sign in using my Apple ID, which I did, the above *...*@gmail.com. This is now what I use to sign into the Cloud.

OK, so moving on, I have gone into the settings in my Ipad and adjusted he settings to back everything up to the Cloud. But, as most of us are aware, to activate Notes and Mail, we need an @me.com address. So, if I get one, will it conflict with my Apple ID? Will I then have two Apple ID's?

Also, I downloaded the iCloud thing to my desktop on my laptop, it has disappeared, but when I did have it open, it said I need Outlook 2007, which I don't have. I'm a bit confused by what gets backed up. On the iPad I have my *...*@gmail.com addy set up for forums and such, and a private email for everything else... why do I need an @me? Confused!