1, Can you get an external hard drive to save music, photos and video?
yes, but why not look at it in a different way?
i dont really stick to a single pc with all my itunes media (all my movies and apps and songs) because my job means i do a lot of moving about from pc to pc wherever i am.
So, i purchased a portable pocket external hard drive. a western digital 1 tb (1000gb) thing, cost me around 50 big ones. just a standard off the shelf extra drive. So I keep my permanent and current up to date media library on this, and carry it about with me permanently. Then, when ever i want to back up or sync or just copy movies/apps/songs back and forth to my ipad2 i just plug this usb drive into any computer that has itunes installed and go from here. works a treat. means im not tied down to any individual computer.
Nope, i cant plug this drive directly into the ipad, but then does it matter? no. my life and ipad life is uber uber flexible and easy.
2, Do you need a PC to use the iPad 2 in the beginning?
yes. but your local shop can do this and initialise things for you.
Ultimately, you have to look into the near (very near) future - in just a couple of very short months the new iOS5 will be released. This will mean no hard wiring from now on! itunes/media syncing, initialising and firmware updates all over the airways. awesomeness.
The ipad2 certainly replaced the need i had for my laptop, which i no longer own, but then i also heavily use desktops for both work and pleasure, which the ipad cant even come close to dreaming about replacing.
I do basic office admin on my ipad with great success in work (ie, letters, accounting, contacts, schedules/diarys, invoicing etc etc), but for me and i suspect the vast majority of users, the ipad is basically an expensive personal media viewing gadget/toy. fantastic for music, videos, gaming and browsing the web!