I think in the end, they're all so close to eachother in functionality, and in image quality, that worrying about the brand is low on the list of concerns - and all can perform in simplified 'auto' modes that make it super simple to use, or as advanced as you're willing to go.
That said, here's a few things I'd consider in your shoes:
Have you handled several models? Try this, as each has different button layout, grip design, weight and size, ergonomics, etc. You may find one brand to be more comfortable, familiar, ergonomically fit for you, or of the right size and build. Whether Sony, Canon, Nikon, Pentax, or Olympus, each has their own design and some folks find some work great for them and others downright unusable.
How to you plan on shooting? If leaning towards a mix of viewfinder and 'live view', or using the LCD for shooting, the Sony Alpha system is usually the best choice, with Olympus second. Sony's system is the one that works the most 'normally' in live view mode, in that it doesn't slow down the camera's performance in focus, shutter speed, etc. - it essentially acts just like a P&S camera. Other live view modes are cumbersome and slow, designed to achieve accurate focus while working with tripods or macro modes - not really for handheld walking around. On the other hand, their live view system does compromise their viewfinder size, so if you intend to live off that viewfinder 99.9% of the time and aren't really interested in live view, then the Sony system probably isn't the best choice. Note that any DSLR viewfinder is far bigger than P&S camera viewfinders, so even Sony and Olympus' smallest viewfinders on DSLRs are better than P&S.
What key features are crucial for you? Figure out if there are any 'must have' features you want and are not willing to compromise on, then you can weed out any cameras that don't have those features. The afformentioned live view, 100% viewfinder, mirror lockup, battery life percent meter, etc. Don't get a camera that doesn't have something you really want - you'll end up missing it and disliking the camera.
I ended up with a Sony Alpha when I first came over from a P&S ultrazoom...it took a lot of looking, and handling the cameras to decide. For me, it worked - I didn't want to compromise on having live view capability, even though I only use it for about 25% of my shots, I wanted the live view to be just as fast and usable as viewfinder use, I wanted a battery that read out life remaining in percentages instead of a bar graph, I wanted a substantial grip and heavier camera, and I wanted in-body stabilization. At the time, Sony had all those things on their entry-levels. I shot with that camera for about 2 years, and moved up to a higher Sony model in November last year, to add some additional capabilities. But feel and handling of the cameras was crucial - in between my first model and my current one, Sony released a trio of entry-level cameras with a different design, and I found them very uncomfortable ergonomically for me...so not until they released the A550 model I have now, with a more traditional deep grip design, would I consider getting another Sony. For me, Nikon or Pentax would be my second choice, if I hadn't picked the Sony - again because of feel. For me, Olympus and Canon cameras are very uncomfortable grip designs. Someone else might be 100% different.
So if live view is important to you, the Sony is certainly one of the better choices out there, as long as you find their design and ergonomics to fit you well...if not the best choice. Best of luck!