I disagree with other answers that this is simply regional variation, with no difference in meaning.
While I'm sure there are regional variations, and certainly the core meaning is the same, to me (native southern UK)
the meanings are definitely slightly different: The phrase "making a decision" is the more common phrase.
It can refer to the actual moment where a course of action is chosen (and just that moment), but also sometimes to the whole process leading up to it (where one might undertake research, have discussions, think and so on, in order to prepare oneself for the decision itself): "
The committee took several months to make a decision."
The phrase "taking a decision", by contrast, only refers to the decisive moment itself, and not to the process leading up to it.
It has more formal connotation, and an implication that the decision will have serious consequences, and that the person deciding will be responsible for them; it has a sense of finality about it.
Some examples may help clarify: I haven't made a decision about where to go on holiday.
(Informal, consequences not serious, nobody's going to hold me to account.)
The president took the decision to invade Elbonia.
Bob was fired because he took the decision to outsource the call centre to Mars.
The decision-making process took a number of weeks: the engineers did the research and made recommendations, but it was the manager who took the final decision.
In support of this position it is worth using Google to search for "take a decision" and "make a decision" on the BBC News website.
The former are (at time of writing) all about formal decisions (by governments, official bodies, international committees etc); the latter - once quotes from US politicians are filtered out - mostly about personal or informal decisions, and about the decision process rather than any decision being taken: "The Arab leaders should take a decision to stop negotiating..." "
But, as a public consultation into UK future energy needs begins, he said it was time to take a decision on nuclear.
"
"I usually sleep on it, relax and then make a decision which is usually the correct decision.
"
"It's not to say that if you've got to make a decision you should make it in a fraction of a second - that is daft.
"
"When we make a decision, we are supposed to consciously analyse the alternatives and carefully weigh the pros and cons."
english.stackexchange.com/users/3405/psmears
Make decision is the common form used in English.
I want to think about it a bit longer before I make a decision.
But take decision is used in British English.
It means "making an important or formal decision".
I fully accept the decision taken by the committee.
english.stackexchange.com/users/3782/Manoochehr
Per se, there appears to be no difference in meaning.
Even so, "taking a decision" is common in British parlance, whereas "making a decision" is more common in the US.
Refer BetterWritingSkills for more information.
english.stackexchange.com/users/None/
Actually, I think the difference between the two is the final action.
Making a decision implies something you have decided in your mind.
The action to implement that decision may or may not have happened.
Taking a decision implies that the action to implement the decision has happened.
That's my two cents worth.
english.stackexchange.com/users/39701/Dave
For US English only: Make a decision.
Take a position.
A decision is something that is formed through a process.
It is put together, or made.
A position is something that is finished.
The world "position" itself suggests a specific, stable place to which one has moved, or taken.
One makes a decision to take a position.
english.stackexchange.com/users/46506/davidjones
What is the difference between  make decision  and  take decision ? When to use the one and when the other?
What is the difference between 'make decision' and 'take decision'?
english.stackexchange.com
<word-choice><verbs><differences>
english.stackexchange.com/questions/6431
english.stackexchange.com/users/2668/darius
There is no agreement as to whether there is a difference or not between these two phrases, though it apears that "take a decision" may be more common in the UK than the US. One possible distinction could be that "make a decision" implies that the decision has been made whilst "take a decision" implies that the consequential actions of the decision have taken place. This is simply a regional variation with no difference in meaning. The core meaning is the same.There is a slight difference, as "making a decision" is more common. Using Google search will show the difference."Taking a decision" is more common in UK English, whereas "making a decision" is more US English.There is a difference; making a decision means you have decided on the course of action, whereas "taking a decision" means the action you have chosen to implement the decision has happened.
There is no agreement as to whether there is a difference or not between these two phrases, though it apears that "take a decision" may be more common in the UK than the US. One possible distinction could be that "make a decision" implies that the decision has been made whilst "take a decision" implies that the consequential actions of the decision have taken place. Per se, there appears to be no difference in meaning. Take a decision is used in British English and "taking a decision" only refers to the decisive moment itself, and not to the process leading up to it. Making a decision implies something you have decided in your mind. Make a decision is perhaps the most common form used.    
Both forms are used and they generally mean the same, although some believe that "taking a decision" is common in British parlance, whereas "making a decision" is more common in the US.  Some claim that making a decision implies something you have decided in your mind, and that taking a decision implies that the action to implement the decision has happened.  There is no agreement as to whether there is a difference or not between these two phrases, though it apears that "take a decision" may be more common in the UK than the US. One possible distinction could be that "make a decision" implies that the decision has been made whilst "take a decision" implies that the consequential actions of the decision have taken place.
This is simply a regional variation with no difference in meaning. The core meaning is the same. There is a slight difference, as "making a decision" is more common. Using Google search will show the difference. "Taking a decision" is more common in UK English, whereas "making a decision" is more US English. There is a difference; making a decision means you have decided on the course of action, whereas "taking a decision" means the action you have chosen to implement the decision has happened.
Take a decision is used in British English and "taking a decision" only refers to the decisive moment itself, and not to the process leading up to it. Make a decision is perhaps the mosst common form used.     Per se, there appears to be no difference in meaning. Making a decision implies something you have decided in your mind.
Some people would claim that "make a decision" is the common form used in English. There may be a regional variation, with "take a decision" being more prevalent in the UK. Some people would argue that there is no difference in meaning. Making a decision implies that you have decided. Taking a decision may imply that the action required to implement your decision has taken place.