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I guess it also depends on the products you're selling to some degree. If your products are also available at dozens of other commerce sites, you'll have to go out of your way to make crawl-able pages for these products; present more in-depth information about them, etc. But you should do that anyway.
The main SEO-related thing I see being done wrong with commerce sites is too much focus on making the site crawler-friendly, and not enough focus on making it user-friendly. It's great if you get your site to the top of the rankings, but it's useless if your traffic doesn't convert.
Secondly, friendly to crawls and friendly to the users like pleeker said is more of a balancing act than with an informational site. Look around and you will see dozens of sites that rank well, but navigation stinks, most often this isn't because your competitor is inept, it is because they gave up some user friendliness infavor of being more crawler friendly. You'll say you can build a better mouse trap, but most likely, you'll have to make some sacrifice as well along the way. If your lucky and good, you just might make better sacrifices than they did.
Good Luck