One website that has been very helpful to us in researching and planning our travels is BootsnAll. They have ticket deals, suggested itineraries, and best of all, lots of articles written by travelers who have been there and done that!
Check out their Round-The-World page for all things global. They have monthly postings of some very inexpensive RTW ticket deals...like this one, for instance, which is currently enticing me! What a deal...I have paid $1200 before just for a round-trip flight home from Hawaii to Tennessee!