Lately I’ve been thinking, podcasting, and writing about the iPad a lot. As a result I’ve received a lot of email and Twitter traffic asking if I think the iPad software and hardware has evolved to a point that it can replace a Mac. The answer to that question is, “it depends.” More importantly though, that’s the wrong question. I think it’s a mistake to get hung up on whether or not an iPad can replace a traditional computer. It's like asking if buying toaster means you can get rid of your oven.
Instead, consider whether or not an iPad in your life makes things better/easier/funner than things are without an iPad. This is not a zero sum game. It’s okay to have an iPad and a Mac. Nobody’s judging you here.
The iPad is so versatile that the reason for its place in your life varies with the individual user. With my iPad I'm better able to review and annotate legal contracts, read Thelonious Monk sheet music, present evidence in court, edit pictures, and answer email while sitting in the garden. These are all things I’ve done in the past without an iPad but are now easier and more convenient with one. I've got a different list of things that I prefer to do on a Mac. Using an iPad because it is better at some things but not all things is okay.
The right question to ask yourself is not whether you need an iPad to replace a Mac but instead whether or not the particular things an iPad does best for you are worth the cost to buy one.