My suggestion is this: first of all you need to track your SEO acquisition cost, see this link:
http://www.kaushik.net/avinash/2010/12/best-downloadable-custom-web-analytics-reports.html
The second thing is to look at the data: if your ROI for SEO acquisition is positive my suggestion is to take advantage of all of the traffic that you can. In other words, SEO traffic is free and you can't know which is the impact that being listed for many many keyword could have on your overall conversion, so take it all.
The usual scenario is that on e-commerce website, informational keyword doesn't convert directly (ex. "laptop", "best laptop", "laptop performance"), instead of transactional keyword that converts (ex. "acer aspire xxx buy online" ...).
What people don't see, in my view, is that is quite impossible to track the benefit of having your brand exposed trough the overall search funnel (awareness, interest, learn, shop, buy).
So my suggestion is, since your SEO ROI is positive, to take the most traffic that you can, both from specific keyword and from general keyword giving the best content that you can to your visitor. Make sure to follow the rule that the visitor position and what they find on your website must be aligned. I think that visitor are asking for something trough they're search query, you need to provide the best answer possible to them in order to give the best experience possible and you have to make it the most easier for them to have this experience (in other words: if your website usability is a sh*t and users don't understand how to take action on your website, it's less likely that they will take the desired action on your website instead of having a good website usability and good content :).
What are your visitor looking for ? What do they wants ? I mean, if a visitor search for "acer laptop performance", what do they expect to find on your landing page ? How can you provide this to your visitor ?
I think that this will improve your SEO conversion rate, your brand loyalty, authority, trust etc.
Then you could implement a few other strategy to improve CR specifically. My suggestion is to engage with people, in some way. The best thing that you can do, IMHO, is to create a communication channel between you and your visitors. It could be trough an email marketing strategy, it could be trough your blog, twitter, facebook etc etc, it doesn't matter.
I think that this rule, in general, is so f*cking important in our work: if people don't (or can't remember) that you exists, why do you expect that they are gonna buy from you ?
I mean, let's say that you catch up a visitor that is searching for an informational keyword like "acer inspire review". And this visitor land on your landing page. We can suppose that in that specific moment the visitor is not ready to buy (looking for information) BUT it could be ready in the future. We cannot know when.
So two things happens: the first one is that if the content you provide is good, you create a positive experience in the visitor mind (I get from this site what I'm searching for), the second one is that you had a point of contact with a potential client.
And I think that you have to leverage this possibility. If you engage, if you create a communication channel, you can communicate with the visitors saying that "you are alive". This process will surely improve the possibility that the visitor will buy from you when ready: the visitor knows that you exsist and when is ready to buy.. You're simplifying the visitor experience.
Why ?
Because if the visitor wants to buy a specific produtct, and has had a good experience on your website, and you offer what the is looking for, the only action that he should take is visit your website / click your email link and buy instead of spending hours searching for another online store from which to buy.
etc. etc. :))
