To be honest I'd say that it isn't as complex as you might think.
If it were me I'd start with a theme that uses your ecommerce platform of choice. You need to know that the shop part of your website will do what you need it to do (shipping, tax, bundles etc) as it can be the most limiting factor. Depending on how much continuity you want in your website often the styling of the store is the more difficult (as it is treated as a separate plugin and may only pick up certain default styles).
There are lots of high quality pre-made themes that you could pick up that will allow you to easily style your website across both the store and other parts of the website and often they build in many plugins/sliders/shortcodes for free. Yes you pay for some of them but they aren't expensive and you have the benefit of support (I would only ever recommend well supported themes or elite authors). Many of themes will style your portfolio/gallery areas and make it easy for you to create the archives/photos/videos areas. If you find there are some missing functions that you need to fill it is then less of a hassle to find plugins to cover those areas. For elite authors they've typically anticipated most major areas of use and you don't sound like you've got anything too tricky in mind.
I've used Mayashop and it is a very flexible theme with 10 sample home page layouts. You don't have to use the shop as your main home page either it can be just one area of your website. It has good documentation and a large user base. There are other newer themes that I've yet to try.
Hope that helps. In my experience of doing WordPress sites exclusively for about a year and half, the ecommerce can be the stick in the mud, so I'd start by making sure that is sorted. Woocommerce is a good place to start if you want a free flexible solution, but it isn't the only one.