there is always a chance of some kind of attack... it doesnt matter what system you are on....
lots of bad stuff happends on the interwebs....phones/pads/tablets/pc/mac/linux/freebsd/solaris/etc in ways you dont expect either.... just because your ipad is fairly secure doesnt mean your "safe"
should you worry?.... probably not..... but, how important is your data/privacy to you.... basically, make backups of important documents offline, or on a seperate cloud(s) (like dropbox, google, ubuntu one, etc alot of free cloud services). Dont "daisy chain" your website accounts together like the wired editor did below....
if your using public networks alot maybe you would want to get a VPN (virtual private network) otherwise you may susceptible to Man in the Middle attacks, Honeypots, arp poison routing, network sniffing, etc
im on public wifi quite a bit.... on my android phone, i have an app "WiFi protecter" that warns me of network attacks.... my alarm goes off about once a week.... these are network attacks... it doesnt matter what platform your on.
Safari/iOS6 was just comprimised at the pwn2own hacker contest in september:
http://securitywatch.pcmag.com/none/302865-iphone4s-hacked-at-mobile-pwn2own
you dont even need to click links in emails because apple products by default download the images in any viewed email... this attack affects your home router thru your idevice:
http://www.informationweek.com/security/vulnerabilities/iphone-ipad-email-attack -could-compromis/240142933
hackers deleted wired magazine editor's iphone/ipad/macbook remotely after Apple tech support *gave* the hackers access to his iCloud account..
http://www.wired.com/gadgetlab/2012/08/apple-amazon-mat-honan-hacking/
many ppl got their itunes account hacked and their gift card money stolen, 120+ pages of PO'd people:
https://discussions.apple.com/thread/2665383?start=0&tstart=0
cross platform trojans are out there.... affect linux, mac and windows:
http://www.cwcs.co.uk/blog/2012/09/linux-hit-by-cross-platform-trojan.html
well that was fun feeding your paranoia...... important note: stay off the internet 😉