As I have said from the start, Their are advantages and disadvantages to both. The main advantage to an extension tube being the cost. The macro lens is a purpose designed tool. If you think you will be taking a lot of close up photos, you will not beat the quality. Tubes are cheaper, but in most cases they remove a lenses ability to focus to infinity, they decrease your DOF, and they can potentially increase color aberrations and distortions (mostly around the edges of the image) when used with zoom lenses. Sorry to have a differing opinion than you dudemanppl...
btw you can always ebay a set of cheap extension tubes, i picked up a set for 6 bucks