I'm getting increasingly annoyed by the current IBM advertising campaign: 'what makes you special?' Here's the one thing I've learned building countless websites for large organisations - you are not special.
More or less everything you want out of your new website, or your new CMS, is more or less what more or less everyone else wants. Accept that, use what comes 'off the shelf', and you'll be up and running in no time. But if you insist on being different, and customising the off-the-shelf solution to the nth degree, you'll spend unjustifiable amounts of time and money, for which you'll almost certainly never see a decent return.