So if you’re already an iPhone owner, do you need the iPad too? The short answer is that it really depends on how you currently use your iPhone—and what you want out of the iPad. Think of it this way: If you’ve ever found yourself wanting more from your iPhone, you might consider investing in an iPad. Do you watch a lot of videos on your iPhone? If so, you’ve probably wished the display was larger. Are you a gamer? iPad games blow iPhone games out of the water.

My conclusion: I’m an iPhone 3GS owner. And at the moment, I’m not rushing to the store to buy an iPad--though I'm open to changing my mind. But don’t let my indecisiveness sway you either way. Consider these factors:

Price: Deep Pockets Required

For obvious reasons, the iPad is a much bigger investment than the iPhone 3GS. Pricing depends on the amount of storage the iPad includes, and whether or not it has support for 3G networks. An iPad equipped only with Wi-Fi connectivity costs $500 (16GB), $600 (32GB), or $700 (64GB). The Wi-Fi-plus-3G version, available later this month, will cost $130 more at each size—$630 (16GB), $730 (32GB), and $830 (64GB). Of course, if you get the 3G version, you’ll also have to pay for a data plan. You'd pay either $15 a month for 250MB of data, or $30 a month for unlimited data.

By comparison, the iPhone 3G is $100 while the newer and faster iPhone 3GS starts at $200 (with a two-year contract). Unlimited 3G data plans for the iPhone cost $30 as well on top of your voice and text rates. Call me cheap, but the thought of paying for two separate data plans makes me shudder.