For the past 2 weeks, my desktop computer has been disassembled, and my wife and I don't even miss it. We both have a tablet, and I have a laptop as well, which I use for photo processing once or twice per month. We just talked about it the other day, that we don't even miss the Desktop.
We can do all our online activities, reading email, social networking, and even keeping in touch with family via Google's lookout or Skype. While I do sometimes use the laptop, for processing pictures, I don't even need a powerful machine to achieve that, and the laptop does it without breaking a sweat.
I tried downloading and processing the images on my little 7" tablet, but this form factor is only good for reading. If I were to download and edit images on a tablet, it would need to be at least a 10.1, and with more muscle than my little 7" Prestigio.
Since I am an IT professional, who spends like 99% of work time in front of the computer, when I get home I don't miss the monitor, so I usually read on my tablet at night. While I don't think you can get everything done with a tablet, even if you have a top of the line tablet, a powerful desktop is no longer a requirement for everyday usage as it was in the past. Every household had at least one powerful desktop, and maybe a laptop, that was mostly for Word processing, a little surfing and emailing. But photo editing, and heavier stuff needed the desktop power.
These days, even the lower category laptops can handle much more than what laptops 10 years ago could.
I just installed linux on a sub $500 laptop, which had 4 CPU core's, and 6GB or RAM. Now it was a joke running Ubuntu on that machine, of course, I could max out the CPU if I start Trans-coding, decoding, encoding video, but then I wouldn't buy that cheap a laptop. That laptop, can do all that is needed for a regular household, and then some.
I would argue even that having a Decent Laptop at home, and a tablet would cover all needs. But then again, that's just my opinion.