For me, the best use is making beans.
I find that home cooked beans have a much better taste and texture than from cans.
The pressure cooker can make them in just about an hour from the moment you pour them in the pot to perfectly tender, and no presoaking is required, so I don't have to plan a day in advance.
cooking.stackexchange.com/users/1393/Michael Natkin
It's a convenience and a time saver.
The high pressure simply raises the boiling point of water which raises the cooking temperature.
Anything you need to boil (but not evaporate) for a long time will go much faster using it.
Of course without the lid it is also a nice heavy pot.
Canning requires the higher temperature to kill botulism spores but most recipes that call for a pressure cooker will simply take longer.
If you haven't used it in 10 years you are probably fine getting rid of it.
You could send it to me for example. :)
cooking.stackexchange.com/users/2001/Sobachatina
a) Send it to me :) b)
Pressure cookers are good for cooking something like lamb shanks (or other tough meats), which would normally take several hours of braising before becoming tender.
In a pressure cooker, you could probably do it in less than an hour.
cooking.stackexchange.com/users/2047/Bob
I like to use mine as a high pressure steamer.
Pour a 1cm layer of water into the pressure cooker, put a small rack in (came with my pressure cooker) and heat the cooker until the water boils, put your veggies on the rack, close the cooker and cook for two minutes or so on the highest pressure.
Never tasted broccoli that was so fresh.
You could use a steam oven to get the same mode of preparation with more convenience, but it's very pricey.
cooking.stackexchange.com/users/1163/Erik P.
Pressure cookers use higher pressure to raise the boiling point of water, which means that you can cook at a higher temperature.
That leads to shorter cooking times.
It is especially useful for making braises, stews and stocks.
My personal favorite recipe to make in a pressure cooker is Alton Brown's Pressure Cooker Chili.
I've made the recipe without a pressure cooker and it takes 3-4 for the meat to become nice and tender while the pressure cooker can do it in 25 minutes.
http://www.foodnetwork.com/recipes/alton-brown/pressure-cooker-chili-recipe/index.html
cooking.stackexchange.com/users/2053/John Roberts
You can use it to make a version of risotto that doesn't take any stirring.
cooking.stackexchange.com/users/1816/justkt
You can make vegetables soup in minutes.
Steel cut oatmeal, very fast too.
Basically anything that would stovetop cook for hours can be done in 20-35minutes mostly.
We did oxtail soup for dinner just last night in an hour, start to eating.
And vegetables can be steamed to perfection in just a few minutes, with some danger of overcooking.
cooking.stackexchange.com/users/2045/Laura Thomas
pressure cooker is one of my MUST HAVE in my kitchen because aside from saving me a lot of time tendering my meat
but it also save your electric bill for electric stove.
cooking.stackexchange.com/users/None/
Laura at plawingwithfireandwater.com uses her pressure cooker to make a cream croquant.
Pour 35% cream in your cooker to 1/2 an inch, cook for ten minutes at full pressure.
You will get a crunchy caramelized bit of gorgeousness made solely with cream.
cooking.stackexchange.com/users/None/
Pressure cookers generally are ideal for food items that require moist cooking methods that take a long time.
Generally, the can be employed in lieu of: Long boiling or simmering, as with beans or brown rice Stews and other braises Long steaming
cooking.stackexchange.com/users/14401/SAJ14SAJ
We were just clearing out our kitchen and stared at this brand new, unused pressure cooker we got for our wedding over 10 years ago!  We've never felt the need to use it before.  I know it's supposed to be able to cook things really fast, but is this really an essential appliance?  We're debating if we should give it to someone else.  Before I do that though, I think I want to try it a few times. What kinds of things would best demonstrate its usefulness?
What types of cooking are pressure cookers most useful for?
cooking.stackexchange.com
<equipment><pressure-cooker>
cooking.stackexchange.com/questions/5873
cooking.stackexchange.com/users/1504/Wil
Pressure cookers are convenient and save time, effort and energy. They are good for steaming or for making stocks, stews and soups, and can quickly cook lamb and other meats that would otherwise take hours to become tender. You can also make a risotto without needing to stir. A pressure cooker will reduce cooking time and is especially useful for recipes that need a lot of cooking time.
Pressure cookers are good for cooking something like lamb shanks (or other tough meats), which would normally take several hours of braising before becoming tender.
It saves time and electricity for recipes that need moist cooking and a lot of time.  You can use it for steaming vegetables. It is good for quick soups and stews and for risotto with no stirring.