Fransisco, are you using canononical tag to any effect on pointing the sub pages to the head category page?

I think theres a lot to be said good about exact match domains.........visitors see the words in the domain name and thats not a bad thing. Everybody got a little weighting from EMD`s, now they dont, so your not losing anything over the domain naming, just a levelling. Its not a penalty.

Whether to brand or not is another question and of course if you do then brand domain will be best. (Google now loves brands more than life itself, so worth considering.)

Consider this scenario. You are New York Lawnmowers, you have domain newyorklandmowers.com and when you place your brand links...they are in fact possibly coincide with anchor text, Over oprimisation penalty? Else you can only use URL or varying forms of anchor text.

If you are Lehman of New york and sell Lawnmowers you can be lehman.com and use Lehman as branding links, the URL, a small percentage of New York Lawnmowers anchor texts and other variations. (Dont forget blank images too)

Google will find the brand name without even fitting it in the title, its that smart, from the content and geolocation. Leave the title for the main target money keywords. Your subpages will not carry the same weight as the index page, but of course build links to them. You might find your subpage is against keywords on another site index page. Thats unavoidable.

PS. I changed my brand to the name Google but all i got was webmasters complaining about dropped rankings