Design and implement a new menu system for wordpress site

currently the menu system on my wordpress site does not allow me much flexibility I would like a new menu system which is fast looks good and I am able to add new menu items using the native wordpress admin console. I am looking to achieve exactly the same menu system as this site http://www.itgovernance.co.uk. At some point I will want to completely revamp the site with a brand new custom design. my current site is www.redstarcbt.com.