Yours is not a new question, but I think over the past 5 years the answer may be a bit more difficult. A quick look at the history of Laptops reveals that the Laptops being sold today are tremendously faster, lighter, more cost effective, and a good choice for people requiring full mobility of all of their computer applications. Newer laptops are more power efficient too. But allow me to through out a word of caution regarding laptops. There is a lot of JUNK being sold out there. Price isn't always the best indicator, but it seems to be a practical one when I say, "You get what you pay for". You can't expect to pay $399.00 and get a top of the line laptop. It's just not practical to think that way. Laptop vendors have done a great job at convincing the laptop market at large that "Laptops are Cheap".
The truth is that a decent laptop built with quality parts and state of the art components and features could easily cost in excess of $1,500.00. Some are more than $2,000.00. And yes it's true that you can buy a basic laptop for under $500.00 that will run all of the programs that the Big Brother runs. But for how long? What I'm trying to say here is that a laptop isn't a "Desktop Replacement". Let me tell you why.
Laptops today are pretty much built as "disposable electronics". It's been my experience (over 29 years) that laptops have a useful life of less than 5 years. There are any number of reasons that laptops break down (I repair them for a living). Fans wear out, hard drives fail, heat weakens circuits, batteries fail, CMOS batteries fail, video chips and LCD Screens fail and the list goes on and on. The other issue with laptops due to their mobile nature is that they get broken quite often. One mistake and the laptop could be toast. One spill of the ole coffee cup and zap!!! So lets make no mistake about the difference between laptops and desktops. The only distinct advantage you gain by having a laptop is that you and all of your programs and data are MOBILE.
Recent innovation by many companies have introduced touchpads into the market. These handy little devices, with a little use of other technological advances like keeping your data in the "Cloud" have taken many applications completely mobile without even being on your touchpad. The same goes for SmartPhones. So you have to ask yourself the big question, and that is, "Just how much of my computing needs to be mobile?"
So let's move on to the Desktop. For me, the Desktop is the ROCK. My desktop is what I use to backup all of my customer's data, my own data, and my personal laptop (yes I have both). My Desktop also serves as a server for movies and music for my household and personal network. I use my Desktop to Read and Write CDs and DVDs, and quickly transfer data to any medium I need to move things to. My motherboard processes data from my hard drive at 6GBs, and with my SSD running the show it's fast as a guerrilla with it's hair on fire. My Monitor is BIG and I can clearly see everything I need to see all at once. My Desktop provides a catalog of programs dating back for many years, and when one of my customers calls to ask about pictures they had on their laptop hard drive 3 years ago, I can bring them up and pop a DVD in to revive those old files to a new life for old customers.
All that aside, a laptop can never keep up with a desktop in terms of speed, durability, hard drive or RAM capacity, video capabilities, and sheer overall usefulness. But the disadvantage is that I can't hump that big ole tower around in a tidy little carrying case when I go to visit my Sister in Washington. That's why I have a laptop!!! But I think it's fair to say that over the past 10 years I've probably had 5 laptops, but I've only had to upgrade the motherboard in my desktop once and I recently upgraded the power supply as well. That's another nice thing about desktops, you can upgrade components as new technologies emerge without replacing everything.
OKAY, so you're probably saying that ole High Desert Charlie is saying you should stick to a desktop. Not so. This is John's decision to make and he has to consider a number of variables.
Of course the choice depends a lot on your budget and how you use your computer. If you can afford it, maybe you should have both! You can get a pretty nice Desktop these days for under $500.00. You'll have to shop for the right deal but I promise they're out there. The same thing goes for Laptops. I strongly recommend for my customers that they consider purchasing Off-Lease laptops. I do so because more often than not, Off-Lease laptops are business quality machines with little if any wear and tear. A good example might be a Dell E4300 that originally sold for $2,700.00 that would be available today for around $300.00. Throw in an new SSD and for less than $500.00 you have a blazing fast portable to compliment your Desktop at home.
I do most of my computing at home. Shopping, banking, emailing, facebooking, etc.. so I rely heavily on my Desktop. When I travel away from home, I enjoy my laptop for web browsing, checking email and social networking, but I'd never consider my Laptop a replacement for my Desktop.
Hope this helps.