Your first examples are what I would use if I had more then one product or service. Having a hierarchy in your URLs and site structure is a great way to organize your website both for you and the search engines.
For example:
home page
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products services
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Prod1 Prod2 Prod3 Serv1 Serv2
You can see that the home page is at the top of the hierarchy. This makes sense because it is the portal to the rest of your website. The products and services pages are up next as they are the portal to the individual products and services. Lastly you have the individual product and services pages.
By doing it this way you essentially establish an SEO hierarchy through internal linking. The pages higher up in the hierarchy are going to be given more weight then the pages lower in the hierarchy. This is good because the pages higher up in your hierarchy are going to be competing for more general search phrases while your deeper pages will be competing for less competitive search phrases (a specific product name, a specific service). This essentially is like your inner pages, who don't need as much help to rank well, giving your higher pages, which do need more help to rank well, a boost.
home page
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widgets services
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blue green red clapping shimmying
In the example above you can see that the widget and services pages are very general categories (a lot of competition) and the actual products and services pages themselves (blue, green, slapping) have very specific content (less competition).
Additionally, the hierarchy is clearly represented in your URLs which helps users understand your site better. Since usability is a big part of SEO, it also helps the search engines understand your pages better. (This is very similar to PageRank sculpting which is also achieved by organizing your site this way).
