Call me old school, or out of touch (pun intended) but as big a fan of tablets and the touch-screen enabled operating systems (OS) that run them that I am, I just don't see these devices replacing laptops. I'm a huge Star Trek fan, and I recognize the tablet form factor as the classic PADD from that series. Sometimes with a stylus, sometimes without - it was supposed to be the ultimate informational portal, like unto the paper notebook or legal pad which dominated offices and campuses the world over (at least until this decade) but gone digital with access to a vast computer database at the user's fingertips.

But there are some logistical problems with tablets that aren't so apparent onscreen but become so once you're trying to get things done using one.

• Battery Life - The balance of battery life to performance is only now starting to fall out on the side of performance. Don't forget to plug the thing in to charge it however, because if you do you're going to be grabbing your spiral notebook and pencil as I did for a meeting today.
• Your finger is not a point - A pen or pencil has a sharp point - you can write with one on a piece of paper really small, and get lots of scribbled data into a really small area on the page. Not so with the big mushy fingertip! Unless you're working with a stylus (and most of these are pretty big and fingertip-like) if you think you want to use the tablet in the same way you do a paper notebook prepare to fit a whole lot less information per page size. Sure, you can zoom out to create a massive drawing in some software, but thats kludgey and you can't easily see it all at once and be able to read it like you can on paper with a fine tip writing device.
• To Cover or not to cover - Unless you buy some kind of cover for your tablet you will end up carrying it around with an unprotected screen. Even if you don't scratch it up this way, you still need to be aware that potentially private information might be displayed on it in bright glowing look-at-me fashion as you carry the thing around.
• Tablet stand - If you don't have a cover, you might not have any way to stand the thing up on a desk. Tablets are very hard to read when they are laying flat on a table, so you will definitely want to have a way to have the screen upright. I use an ASUS Transformer with a detachable keyboard. It basically turns the touchpad into a laptop so the tablet can easily be set in a readable position when set on a desk. This is great for me, but if you're like most folks with a regular tablet be prepared to fumble around with some third party solution to keep your tablet in a readable position when you want to put it down for a bit. This is my biggest problem with tablets and the reason why I opted for the form factor I did.
• Weight - Tablets are not light. Holding a 10" tablet will quickly tire your wrist and hand. You will find yourself switching it from hand to hand. See previous point about having some way to put it down. Holding it leaves you only one other hand to enter data if you're using the onscreen keyboard this slows you down even more than lacking a real keyboard will. A 7" tablet might not have as much of a weight problem, but my take on 7" tablets is they're just too damn small - why not just use a phablet or even a smartphone at that point?
• The OS matters - The operating system you choose will define how you end up using the tablet. If you pick a Windows tablet you're stuck with Microsoft's rather limited application set though if you're tightly tied to Microsoft (why?) you might be able to stand it. I find Win8 fails the most basic user interface tests of consistency and intuitiveness, so its not for me. Apple is tied tightly to iTunes which I can't easily run (except in a Virtual Machine maybe). I just want to be able to plug my device in and transfer files to and from it, I don't want to have to load up some bloatware that will then "sync" my information to the device - thats so 1999 Palm Desktop, no thanks! Android works well across the different computer operating systems I find myself on, and lets me work the way I want to - but your mileage may vary.
• Its not a desktop OS - This all said, the operating system is not a desktop OS. You will be able to do LOTS of things you normally do (email, web browsing, some light picture taking/editing, audio and video chat, watching videos, listening to music, light gaming) but don't expect it to replace a real computer for anything more serious. If you want to make a decent video with transitions and titles and post it to youtube, play games with good graphics, do desktop publishing like creating posters or newsletters, or do anything that requires even modest computing power you will want to have an actual computer (be it a desktop or a laptop) hooked up to a big screen to do that.
• The touch paradigm - Tablet operating systems are designed to be driven by touch and this paradigm is something that older folks require some time to get used to. If you're young, this probably isn't an issue, but if you're any older than me you've been using a mouse and a keyboard for a looong time and touch takes a little getting used to. BUT, once you go touch you will soon find yourself swiping your regular laptop's screen and wondering why its not doing anything at least once or twice.
• On screen keyboards suck - The lack of a keyboard for me is a deal killer. I can't possibly be expected to use an onscreen keyboard for anything more than a tweet (which I rarely do anyway). I send lengthy emails, write up meeting notes which are usually several pages, write blog posts (like this!), lyrics sheets, etc. and I need a real keyboard. I type pretty fast and moving to an onscreen keyboard would seriously affect my productivity. If you're not that fast of a typist it might not be as big a deal. The problem for me is that once you add a keyboard (maybe one that doubles as a cover for the screen) you've pretty well made the thing into a laptop. Why not just get a very lightweight laptop instead?
• Why a tablet? - The obvious answer for why folks are buying tablets is: 1) touchscreen 2) battery life 3) instant on. Thats pretty much the benefits of the tablet right there. Which leads me to my predictions:

Predictions I make in 2013

The future of the tablet is unclear. We're moving to a world where Intel is finally creating low power processors to rival some of those found in tablets for power consumption, and as more laptops have touchscreens and SSD hard drives the dividing line between what is a touchpad and what is an ultrabook will probably blur. We're going to see a whole range of new laptops which may rival touchpads in these three areas and perhaps even run the tablet OS of your choice. Its compelling for a couple reasons which soon may be part and parcel of all portable devices (including laptops - which I consider the "perfect" form factor - my preference is a 12" or 13" screen).

What I prefer

Tablets are fun to play with, but thats largely a function of the combination of the touchscreen and the OS. A laptop with a touchscreen running the same OS wouldn't be much different except for the built in keyboard / cover which many folks seem to be adding on to their touchpads as accessories anyway. The add-on keyboard / covers are usually inferior build and flimsy, and they usually have a crappy bluetooth connection which gets unpaired at inconvenient times or has a dinky switch which goes flaky. Give me a built in keyboard and the option for a wireless mouse anytime. I love my Transformer now that its running android 4.3, but only with the keyboard and I never use it without it. The keyboard also has another battery in it so my battery life is double most tablets.