I will be traveling for 20 days in August before starting a study abroad program in Germany. I plan to visit Italy (Cinque Terre hiking and kayaking and Florence) and either Spain, Greece, or Ireland. I MUST take my laptop and SLR digital camera with me

My question is: is it safe to leave my laptop and camera in Hostels/Hotels/Apartments? Or should I invest in a backpack that carries both to take with me every day?

Hostels - not safe. Generally, there aren't private areas to store things.

Hotels - generally safe in a private room. Even better would be using the room safe or hotel safe.

Apartments - same as your apartment at home.

Even if you got backpack and carried both around (which sounds painful!), what would you do with them, for example, while kayaking?

Hope they don't get wet? haha... so hostels aren't safe even if they offer a luggage room or lockers?

A locked locker might be safe. Definitely NOT a luggage room that lots of others have access to.

The best you can do is to control damage.

When I take my computer on a trip, I go with an assumption that the hardware can be stolen.

However, I can take steps to protect my DATA. I don't put personal/confidential data on my disk drive even though I put a hard drive password on it. I keep my data on my SD card and keep it with my passport - either with me or in a safe . You can get an SD card up to 32GB capacity. I have a USB adopter, so on computer without a SD card slot, I can access my SD card using the USB adopter.

If I create a document I don't want to lose, I email the document to myself or upload to my google doc area.

There is "left luggage" storage business at the Monastiraki and Omonia Metro Stations.

Just a word of caution regarding storing your laptop in hotel room safes. first of all, not all hotels, esp the lower star hotels, do not have in-room safes. So you need to research the hotels to make sure they offer in-room safes before booking them. Second, many of the 2* hotels I've stayed in, the in-room safes is pretty small. The safe is plenty big enough to store things like passport or camera or cellphone; but many of them will not fit a regular-sized laptop. (Many of the safes I've seen are about size of 8x11, with the door opening even narrower.)

You can also buy a security locking cable that you attach to a port in the laptop body and wrap around a fixed object, so nobody can just walk away with the laptop itself. (unless they also have a nice bolt cutter or something!) The locks run around $30US.

If you plan to prebook your hostels, I would ask whether or not they have private, lockable lockers/cabinets, especially if you plan to stay in a dorm room (as opposed to a private room). The ones I've stayed in recently had lockers of some sort, although you might need to provide your own lock.

I can't imagine carrying both of those around with me all day, every day.

Greece , Ireland , Italy , Spain

Unless you are flying I would chop two of these countries for only 20 days of travel.

I will be going to Italy for 9 days, then EITHER Ireland, Spain, OR Greece. I would never try to do all of that in 20 days

Most hostels will have a safe storage area for things like laptops and cameras. It usually costs a few bucks though to utilize these areas. On the other hand, I usually carry my laptop with me while I'm touring because I consider and extension of myself...