post fix?

This going to seem strange coming from someone thats had 2 years playing around with linux, and i feel its stupid question asking, but i going to. lol

I have my linode set up with apache2/mysql/php and wordpress installed with round about 3rd of the site built, one of the things i not sure about is how to get inquiry's from my website into my email box. I have seen a plugin for wordpress that's meant to handle this, in some shape or form. I have post fix installed and came across a guy that talks about reverse dns for your domain name and changing /etc/hosts name to domain along with the domain being put into hostname -f, which mine returns tobots, i just need to add the .co.uk. What confused me about his tutorial was the fact he mentioned google apps to handle all in and out going emails cause if its done by smtp or whatever its called in linux, this can or will use a lot of cpu etc. So he mentions google apps, and then does nothing else after reverse dns. lol

Can you guys share a few thoughts on the way you have things set up and why?

Really i just need a simple system set up where i can send and receive for now.

Look forward to your replies.