Back when the original iPad hit the scene, virtually everyone was questioning its purpose and place in the market. Was a fourth device (the others being a desktop PC, notebook and smartphone) really necessary? As it turns out, the answer to that question is a resounding "yes." It may have taken some time but tablets have now solidified their place among our other tech gear and have created an entirely new ecosystem to go along with it.

The success of tablets has come at a price, however: cannibalizing PC sales.

In fact, tablet shipments are expected to outpace those of PCs in the fourth quarter of this year and by 2015, annual tablet shipments will top PC shipments according to research firm IDC. Over the next 12-18 months, IDC believes large smartphones (phablets) will begin to eat into the smaller-sized tablet market.

Bob O'Donnell, program vice president for displays and clients at IDC, said the device world has seen several iterations of cannibalization impacting different categories. The last few years have focused on tablets cannibalizing PC sales.

Looking at the hard numbers, total PC shipments accounted for 28.7 percent of the smart connected device market last year while tablets were responsible for 11.8 percent and smartphones garnered 59.5 percent. Looking ahead to 2017, PC sales are forecasted to drop to 13 percent while tablets will account for 16.5 percent and 70.5 percent, respectively.

The good news for consumers is that as demand shifts from PCs to smartphones and tablets, so too will the average selling price of the collective market from $462 last year to $323 by 2017.