Hey Jason,
Estelle's answered most, but I'll throw in my $0.02 as well:
Can you upload your photos on them out in the field without hooking them up to a laptop?Yes, if you shoot JPG. The Camera Connection Kit is about $35, and works a treat. I couple it with an app (WebAlbums), and can review photos straight from the DSLR and upload to Picasa or Facebook. Not something you'd use for super great photos, or if you were doing RAW work, but as a companion to take with you when you're on holidays, to pick the good photos and upload them to make your friends jealous, it's excellent. I don't take the laptop away with me any more, just throw the camera into RAW+JPEG mode and take the iPad.
(the iPad can copy the RAW files, but you can't run them through any convertors to actually use them. So there's little point, especially if you've got a smaller capacity iPad)
Are they good as navigator, or are they to large to mount and use effectively? ( I have a chepo 7in GPS that works well and is large when mounted to the windscreen)I've heard very good things about the Hema Maps app, but have never used. I too have a cheapo 7" GPS - it's good and is probably bigger than should be stuck to the windscreen. If using the iPad as a nav, you'd probably want one of the RAM Mounts that attaches to the floor/trans tunnel of the car. I've heard the actual GPS works very well. I imagine it would be great from a usability perspective.
What is the battery life like."Depends"
We get a few day's general use out of ours around the house on Wifi. We generally hook it up overnight to charge though. When I've been away, getting a few day's use out of it has been more than achievable.
Is there enough storage on them?We've got a 16Gb one, and I'd like more. That said, we don't hold a heap of stuff on it. We've both got iPhones for our music, so the iPad is just for books, photos and misc other stuff like that. You can now buy an external HDD that will hook up to an iPad so you can carry HEAPS of data with you. Of course, battery life will take a hit if you keep it connected, but it's an option if you need it. Is good, apaprently, for downloading RAW files from your camera, and saving them across to the external HDD for processing later with a PC.
Are the cameras in them any good? Not really
. You wouldn't do anythign serious on them, but they're great for snapping a photo of the dogs to put on facebook. Really, any compact camera in a tablet or a phone is going to be pretty junk if you're used to shooting RAW on a proper camera with decent glass in front of it. Think of it as a bonus for casual stuff like that, and you'll be happy with it.
Can you convert your DVD to play on them yet?Yes, but I've never done it. You'd need some form of DVD ripping software, and the ability to transcode it to mp4 or such. It's not something I've ever had the time or the inclination to do, but I know it can be done.
As for iPad vs laptop, they're both different things for different jobs. If you want to do video editing, or sit down after a day of photographing, then you'll fond no substitute for a good laptop with a big external HDD. If you need the power, then that's what you need. But for general web browsing, etc, the iPad is excellent. My wife has stolen "ours" now, despite not wanting anything to do with it when I bought it home. It's easy to use, it's handy, it's always on and ready to go - it's something we use all the time. This is particularly annoying for me, since I had it all set up with all my work stuff on it, and now I never get a go :'(
.
We've got a baby little HP netbook at home as well. It used to be our "traveling" machine - it's half the size of an A4 piece of paper. But you can't do any real work on it - the screen's too small, it's not got enough HP under the hood (despite 3Gb RAM, and all the good stuff), and the keyboard is too cramped. We've hardly touched it since the iPad has arrived. I would not recommend it. iPad+CCK does it's job these days. My work laptop is a 14" proper laptop, and it's great as a workhorse machine. But despite being at the smaller end of the scale, if traveling for anything other than work I rarely take it (and it's charger, and external mouse, and and and...).
I'm holding off to see if the iPad3 does come out, at which point I'll try to acquire one through work
. The promise of a bigger battery and LTE/4G data would suit me down to a tee. Keep in mind that this time every year "new iPad" rumours start thick and fast. We all know how the sure-bet rumours about the iPhone 5 last year ended up.
Good luck! They're expensive things, but they're great.
Matto