Originally Posted by alex

301 redirect is good, but only if your domain is already getting traffic and has back links, otherwise no one will find them. If you set up a mini site for each domain, concentrating on the relevant keywords, the mini sites will rank in Google and enjoy increased traffic. If you then place links to the appropriate pages in your main site and encourage users to follow them then ultimately the main site will rank higher and the overall exposure will be greater. It obviously means slightly more work, but the mini site doesn't have to be extravagant.