Calculators are helpful to me because it works faster than on a PC, or my Android phone. Ergonomics play a large factor. However, once the data set I'm using goes over 10+, or I'm using paper to track portions of calculations, it time to move to a PC, it also justifies the setup time.
I get to use most of the functions on my FX260, as I've had with all its ancestors. Some more than others.
There are USB calculators than allow you to pass the data sets to PCs. But they charge far more than an FX260,tend to be large, you'd have to justify its cost on the frequency of use. Basic USB calculator keypads alone cost more than many scientific calculators.
Smartphone, iPad or equivalent could be the final death knell for professional use of calculators. A suitably well written app would then have the same form as a calculator but far larger, with beeps and vibrations compensating for the lack of physical switches. I find the iPad form suitable to replace my FX260, but the true size of the FX260, weight, cost, portability and robustness still wins out, so my FX260 is alive and well. But, when I'm on the road and KISS is important, I use my RealCalc Android calculator instead of lugging yet another item.
I had a TI-89 for most of college and loved it. I also used Matlab a lot, like many of you. I realized that I used my TI-89 entirely for hand calculations, but never used it's programability.
Generally this isn't an issue for the desk which is why I think the calculator market is in trouble.
What I really wanted to know, and I think will give us more insight into what calculator we use and why we hate newer ones, is what we actually use calculators (of all forms including Matlab) for these days. I work in embedded design and software, and I rarely use a calculator these days. My main applications are simple math for footprint dimensions and converting numbers between variable bases. What about everyone else?