It's all about use cases. I have many tablets that I use for a variety of purposes. They all fit a certain need.
I have one in the garage that I use as a Sonos (whole-house music system) controller and to occasionally look up shop-related queries (IE - "what is the torque spec on the axle bolt for my bike?").
I have one next to the couch that is also a Sonos controller and I use for weather and "2nd screen" duties. IE - "Why does Con Air's cinematography style look so much like Michael Bay movies?"
I've got one in the home office I use for hacking, many other gadgets I use have tablet-based interfaces.
I have a retina iPad on the nightstand for reading, checking the news/weather/sports/social networks and to control my house lights - part of my bedtime routine.
My most compelling use though is for when I need a light computer for travel. Two years ago, I went to Hawaii for a week on two carry-on bags (including big camera and diving gear). I had my iPad with me and, while there, work had a serious server outage. I was able to SSH into the server, initiate repairs, and get everything fixed while sitting on the balcony in the sun. I did not carry (and could not have fit) any normal sized laptop in the carry on. I also used to it check out various tourist destinations and find places to eat while I was there (which I could have done on a smartphone, true).
I'm an extreme geek, I have embraced the culture of technology, my house is filled with many gadgets that have served me well and others that have served only to drain my bank account. I have no hesitations about buying something if I have even the slightest inkling that it would improve my life/workflow.
In the above, all but the iPads were cheap Android tablets that I dont think I paid more than $200usd for (none of those needs required a whole lot of horsepower).
To speak to your specific interest, tablets are awesome for casual web navigation and almost awesome for note-taking. I have yet to duplicate the ease and awesomeness of a pen on paper for note-taking with any tablet app/stylus combo. Many tablet note-taking apps have great features, but the actual 'feel' of a quality ballpoint pen on wood pulp has yet to be duplicated - for me, I've spent far too much time being 'constrained' by computers to be able to think as freely as I can with a pen and paper. Switching will almost certainly be a painful adjustment. That said, if 'computers' are your native medium, then note taking on a tablet can be a powerful thing.
For example, Microsoft OneNote is an amazingly awesome note-taking app for computer-savvy folks. They really nailed the balance between digital data entry and analog notation while presenting it in a fairly intuitive interface. I've only ever used it on PC, I'd love to see as brilliant an implementation on a tablet. Not sure it's possible without a mouse-'mindset' interface.
Though really, as long as you don't need big horsepower and aren't on an extremely constrained budget, it's not too hard to get your feet wet in the tablet world cheap. I just saw a not-horrible import Android tablet for <$40 on a sale site.