Don't do much web stuff myself but I thought Masterpages allowed for a the ability to create a standardised look and feel to your site, a sort of visual inheritance.
I want to have a menu option from the left side of my page and whenever my user click one of the buttons under my menu option the output should be display in the right side of my page and i also want to put the company logo at the top of the page. Pls see the attachment below.
Even if master wasn't the way to go, you should use objects instead of IFrames. Otherwise you have to validate frameset, objects allow you to stay strict.
But yeah, master are the nicest with the most features.