Do I need to actually build a site for a domain that is going to be redirected to another site anyway? I have a websit for my roofing company and I purchase some domains that should be good for seo (domain name is great keyword search), but i dont know if i need to actually build a site for pr reasons before i redirect the site to my actual site....any help would be greatly appreciated.

Do I need to actually build a site for a domain that is going to be redirected to another site anyway?

No, but you might want to put a basic page there with a hard link to where the actual site IS, just in case.

If you're going to use a re-direct, make sure you do it properly with a 401 Redirect.