Besides the material itself, there are lots of other factors -- Surface : There are smooth plastic cutting boards, and there are rougher ones.
I prefer the rougher ones, as smooth means things are slipping all over the place and its can be dangerous.
Plastic will roughen up with use, but cuts and nicks in plastic boards means more places for germs.
For those thin plastic cutting mats, they're so lightweight that you have to worry about both the food sliding, and the mat itself sliding.
Thickness
: Those 'butcher block' wooden boards look great, but I don't like them for two reasons: I'm short, and it raises the surface that I'm cutting at; they're heavier, and I like being able to pick up my cutting board to take to my stove, as my cutting area is near my sink, not my stove.
Size : Large enough to hold the amount of food you tend to prep at one time, and not so overly large that it's a pain to move /
clean / etc.
I like about 18" x 24" (45cm x 60cm),
but if you're cooking for one in a small apartment, that might be a little large.
(although, one of my apartments was small enough that I used a large board, so I could span the sink, as there was all of maybe 30" (75cm) of counter space.
All this being said
-- I use wood for all vegetables, and plastic cutting mats for meats and poultry, just because it saves me time sanitizing everything between cutting.
(although, I typically try to cut all of the vegetables first, then the meat, just to save on cleaning a knife).
Part of the complaint against wood is that it's very hard to get germs out once they get into wood -- but research has shown that if you clean the surface, wood cutting boards are unlikely to transfer germs to other food, and a well-maintained wooden cutting board will self-heal and continues to be safe over time, whereas plastic can't be simply wiped down once it starts developed scratches from use.
To sanitize wood boards, use half a lemon, and coarse salt (I use kosher salt), and use the cut side to scrub the board.
Rinse, let it dry, and give it some food-grade mineral oil every few months, depending on how humid your area is.
If it's looking sad, you can always sand it down, re-sanitize it and re-oil it.
cooking.stackexchange.com/users/67/Joe
I use two types of cutting boards: wood and [soft] plastic.
The plastic is for meat, or anything that could ruin a wood cutting board.
Wood is for everything else.
If you can afford it, try to get an end-grain wood cutting board.
Bamboo is a popular choice right now (it's affordable and sustainable), but I don't have any personal experience with it.
Most other materials, especially glass, will ruin your knives.
cooking.stackexchange.com/users/None/
Don't use a glass board.
It dulls the edge of the knife and the food you are trying to cut is more likely to slip than on a wood/plastic board.
cooking.stackexchange.com/users/21/Curry
One thing not mentioned is feet/pads on the bottom of the board.
Boards without anything on the bottom except a flat surface can slip.
You can resolve this by adding rubber feet or a damp towel but if you are buying a new cutting board it might be something worth looking into.
Also, check out the size of the board in terms of your sink.
A large board is great for cooking, a large board is a pain in my side for cleaning as it barely fits in the sink and creates a mess just by cleaning it.
cooking.stackexchange.com/users/1511/Chris
How about something on the edge of the board (like a soft rubber "fence" maybe .5
" tall)
that keeps the food from falling off.
I realize this is tricky b/c you don't want the "fence" to interfere w/ the cutting.
But it drives me nuts that food is always falling off the edge (just a tiny amount but enough to make a mess).
cooking.stackexchange.com/users/6395/Clay Nichols
One thing not yet mentioned: For an everyday plastic board, it's great to have one just small enough to easily fit in the dishwasher - easily and perfectly sanitized every time.
cooking.stackexchange.com/users/20183/Jolenealaska
My selection involves: Bamboo for general purpose veg, small bits of meat (e.g. bacon slices), I also occasionally cut meat on it - it is smooth and juices etc run straight off it.
Several Plastic for when I have several dishes on the go or lots and lots of veg and also meat and fish.
Wood for bread, cheese and cooked meat
- It looks nice when I serve cheese boards or antipasti.
I have a glass one but only use it as a heat mat as well as dulling knives it also makes a horrible noise when you do need to cut on it.
I have an endgrain wood board that is designed for meat
(it has a groove around the outside for collecting juices).
But I find it too big, heavy and hard to clean to actually use -
annoyingly it was also my most expensive.
I know people who have granite work tops and do not use a board - This is as bad as glass and will dull your knives also.
Wood boards can also absorb juice - so regularly cutting onions, garlic or "smelly" things may cause your board, and therefore other things you cut on it to pick up the smell.
Wood is also annoying to maintain - it needs oiling occasionally as well as disinfecting.
cooking.stackexchange.com/users/2010/NBenatar
I have heard various debates on the merits of wood versus synthetic cutting boards, and their affect on food safety, knife edges, and ease of cleaning and storage.  What are the pros and cons of the following and why?   Wood versus plastic or other materials  Affect on food safety and cleanliness  Cost to purchase  Affect on knife edge and ease of use
Cutting boards: What are some general tips on purchasing and using a cutting board?
cooking.stackexchange.com
<equipment><knives><cutting><chopping><cutting-boards>
cooking.stackexchange.com/questions/183
cooking.stackexchange.com/users/91/JYelton
Wooden cutting boards have a reputation for storing germs, but research has shown that a well-cleaned surface is generally enough to prevent transfer. Plastic surfaces are often smooth, but develop cuts and nicks that can store germs later. A small plastic board can fit in the dishwasher and sanitised easier, and will not pick up smells like garlic as easily as wood. Plastic boards are the easiest to use and keep clean. Wood boards need to bekept really clean. Glass boards are not recommended.
Plastic boards are good for meat. They are easy to wash, especially if small enough to fit in the dishwasher.  Wood boards are harder to keep clean and neet maintenance. Glass boards are not recommended.