For our upcoming trip 3 week trip to Europe I've decided to leave my laptop at home and travel with only my iPad. Naturally, the two things I worry about most with this plan are theft and damage.
To mitigate the chances of theft, I'll be carrying a Pacsafe Metrosafe 200 bag. I found a great deal on REI's website a few weeks ago and got one for less than $45 with free shipping. The bag has many great security features including slashproof eXomesh lining. Along with a cheap travel combination lock, I'll be able to lock the bag to a piece of furniture in a hotel room and keep the contents safe.
When it comes to damage, my #1 fear was rain. Obviously electronics and water aren't a great combination. When I looked on-line, there are a couple of different companies that make waterproof cases for the iPad. Prices seem to start at $20 and go up from there.
Being an avid hiker and photographer, I've often had to keep my equipment safe in rain. I've found that gallon sized Ziploc bags have always worked well. It turns out that the iPad fits inside one perfectly. As an added bonus, the touch screen on the iPad works just fine through the bag.