Mainly ipad/desktop, then smartphone.
There is also an ancient Sony laptop (2006, so 8-9 years old) connected to the TV but this is getting less and less use since connecting the ipad to the tv is much faster and easier than waiting for the laptop to boot up.
Desktop mainly used for work, ipad used for emailing, youtube, 'casual' browsing, etc. I probably spend about the same time on each.
Some of you may be surprised that the smartphone (iphone 4 on payg) comes last on this list, but I'm not the sort of person who is constantly expecting texts, phone calls nor do I update my facebook or twitter every time I eat, drink, fart or go on the loo. Hence it gets most of it's use only outside the house.
But what about the life expectancy of these things? My desktop is 7 years old, running vista, slower at booting but once up and running is quite usable. Do you think it is time for an upgrade (probably to a macbook air once a new one comes out)
I have an ipad mini and ipad 2 that is used by other members of the house, don't plan on upgrading those, however since the update the latter has become very slow - what a big mistake it was upgrading to ios 8. Marginal new features, mediocre performance.
Iphone 4? Well it does what I want it to do, calls, texts, bit of internet, camera, so I'll be hanging on to it for some time, perhaps until when the 6 becomes cheaper. Just because a new one comes out, doesn't mean that the 'old' one stops working.