Yeah I agree that a tablet (lets open this up to more than just ipads) is more of a consumption device than a creation one but if you are really serious about creation then I would still recommend a desktop over a laptop.
I now have the perfect combination of a desktop with a nice big screen in my room to create the spreadsheets and other documents I need and the tablet to actually use them.
I have the ASUS transformer and it is a great tablet that has hdmi and sdcard, I can surf the net, watch movies, read books, view and create office docs and hundreds of other things that I didn't even know I wanted to do until I saw that there was an app for it.
The biggest issue I have with it as a tablet is having to use an on-screen keyboard but it came with a keyboard dock that, when the tablet part is docked, makes it look and act just like a laptop. The dock also gives it multiple usb ports and increases the battery life by something like 8 - 12 hours. I can transfer photos directly to it and there are plenty of photo apps out there to manipulate them. Using an app is no different than having to find, download and install software on a laptop, in fact app/software are becoming interchangeable.
For me, one the greatest things about the tablet is that it is so much lighter and more convenient to carry around than my laptop and since I have all the documents I want access to in the Cloud I just have to hit the button, the tablet is instantly on (no bootup time or closedown time just to check one thing) and I can access all the volunteer details, timetables, calendars etc.
I have spent a lot of time traveling with laptops of various sizes and now with my tablet and I could not be paid enough money to go back to having to carry around a laptop. Reading books and magazines is so much better when you can hold it in one hand and turn it to portrait so that magazines, especially, look "proper". That ability to turn on and off instantly is fantastic. What do you do when the flight attendant wants to put food on your tray? I just hit the button and slip the tablet into the magazine pouch thing, no waiting for a laptop to close down, or I prop it up on the tray and keep watching/reading/listening while I eat.
Okay...rant over.
Greg