Joomla would certainly meet those requirements. In particular, the writing about site updates part is a bit of a forte with Joomla, as it's a case of creating a new 'article', assigning it to your 'Site Updates' category that you'll have already created. Then it automatically appears in a predetermined 'module', that you've placed on your homepage - in the Header perhaps... or in a box on the left, or right in the middle! - Sounds a bit complicated, which it kind of is, but once set up, it'll all run smoothly, and everything will actually be so much easier in the long-run.
As for a gallery, I think Joomla comes with a few built in options which may cover you, but if not, that's where the wrapper comes in, where you build a separate gallery, like your current site, and then place it within a page on your Joomla site. Another option is to use something like Gallery2, which is a pretty versatile gallery program, again server and database based. If you don't want purchase options, it works really well in a wrapper. If you want to integrate with PayPal, you run into problems though
Contact pages are particularly good with Joomla.
And with the right template, it can definitely have a clean and simple look, and be very easy to navigate through
Phewph!