It would all depend on your skill level and the time you have available ... and how much time you have to read other plugins / themes / and the WordPress source code.
Are you being paid for the project? Is it for yourself?
It would be helpful if you could elaborate a bit ... but until then I'll suggest a workable, cheap, quick solution that may be implemented with varied programming skills.
- Find a workable grid based theme that supports Custom Menus (Appearance > Menus)
- Create a separate top-level category in the WP admin, say 'Catalogue' and a few sub-cats, if you wish, say, Animal, Plant, Human
- Create your products as posts, format the product images / leaflet layout / etc with the WordPress Editor. Set a featured image for each product.
- Create a custom menu in Appearance > Settings (separate from other menus) and add your product categories to that menu as you'd like them ordered
- create a short_code in functions.php or via a plugin to add a 'call to action' to product post content in the wordpress post editor quickly so that each product has a 'enquire more' or some other call to action, ala [call_to_action product='productname', email='email_address'].
- Create a single-post template for posts in 'catalogue' (a quick google search will set you on the right path / there a a myriad of plugins too)
- Create a template for listings of posts in this category (i.e. a archive-type template ala category-catalogue.php) and adjust the loop to sort the listings for you as you wish (most likely not reverse chroniologically) and pull minimum info, like the permalink (to link to the product), a short excerpt as a teaser and the 'featured image'. Add some css to you style.css to render this out in a grid for you.
I am getting carried away ... but Voila! If you're uo to 'hooking into wordpress' then I can suggest a trillion more things to do that a slightly accomplished php dev can do in less than a day (barring the styling ... that always takes me long as I am NEVER happy with the look and keep tweaking)
If you can't code these alterations yourself, most assuredly you'll find plugins coming out your ears for the different bits and bobs I've suggested ... but that should put you on a good starting path :)
Oh ... and I'd stay away from wp e-commerce if I could, the last time I tried to eat 'that bowl of spaghetti' I almost choked to death and it's certainly overkill for what you are trying to accomplish. I've developed quite a few of these solutions so there must be freemium solutions like this in the public domain as well.
I recommend that you still implement the suggestions above with relation to theme modifications as this pulls all the 'catalogue/shop' bits visually together for your user, but here are a few 'quick and dirty' plugin suggestions. They are plugins, so have the benefit of pluging-in on top of any WP Theme so you are not invested in a e-comm-specific theme which encapsulates the functionality you want.
a. http://dukapress.org/features/ (Free, catalogue only mode [can later be switched to full-featured e-comm solution], various other features, ready to use widgets, easy to use API if you want to extend / customise)
b. http://wordpress.org/extend/plugins/eshop/ (Free, catalogue only mode [can later be switched to full-featured e-comm solution])