Hey all... I was the OP (original poster) to this question... and Neville is correct. It seems that this feature does not work for everyone. I'm assuming it's a version issue with Safari.
There was some in depth discussions regarding DNS, but after trying several DNS servers and getting the same failed results, I believe this is incorrect. Everyone that has stated this works correctly for them is using Safari 5.x. I'm using Safari 6.0.
After doing a lot of searching for the correct answer, I believe it's actually a Safari issue with the way typing in to the URL bar is handled. I have come to this conclusion by watching the bar as I type. I'll try to demonstrate here with a couple pictures to show what I mean.
First, if I start type in an address that I've been to, the auto-complete fills in the whole thing and I don't have to type the whole address, like shown here:
You can see in that screenshot that after I type this first few letters, the website filled in itself.
Now in this screenshot, I will attempt to go to Microsoft's website. This is where Safari fails in it's execution.
You can see several things here. Firstly, even though I have typed in the full name of the site (minus the www and .com), to the right of where I'm typing, the text says "Google Search". Safari plans on executing a Google search for the info I just typed in. If you look further down the list of options, you can see one called "Go to Site Microsoft". If I just hit enter at this point, a Google search comes up searching for Microsoft. If I use the arrow key to go down to the "go to" section, I will be directed to www.microsoft.com even though I didn't type everything in.
And this is where the root of the problem lies. By default, if you haven't visited a site yet, a search is always performed. If you have visited a site, you can go to that site without typing the full URL.
It's possible (probable, even) that those users who came from previous versions of Safari might not have this issue. However, for someone new to Mac like myself that started off with Safari 6.0, this will never work.
Again, to show further evidence, if I type in to the URL bar Compuware (where I work), you can see that even after typing this in, the icon on the left is still a search icon, and on the right it will say Google search.
Now, once I finish typing .com to the end, you'll see that the icon to the left changes to a round circle (I assume this is the equivelant of the globe IE uses), and the search info on the right goes away.
So now, when I hit enter, I'll be take directly to the site. Or I can arrow down to perform a Google search.
My initial argument still stands - Safari is broken in the way that it handles unvisited URLs. By following the standard put in place by all the other major browser - IE, FF, Chrome - and providing a Control - Enter or Command - Enter option of adding the .com to the end of the URL, this could be easily resolved.
