What are the important factors to consider when choosing a Master topic? I am a computer science, master student. As I am nearing the end of my studies, I am starting to weight my options for the final "thing", the Master thesis. I already had 2-3 meetings with some Professors offering master topics. The more I think on this topic, the more I get confused.

One of the topics is not really within the area of my interests, or close to something that I would like to work in the future, but the Professor is really nice and quality, I have had good cooperation with him earlier before. And I think that I can further learn from him. 

One of the other options, is much interesting, however I feel as if I am afraid of it. I don't have much experience in the exact field which the master thesis covers. The professor just arrived in out university and I have not taken any of his lectures.

The final option, is one that I feel more comfortable. It might be from a topic that I have worked on for the last 12 months, so I can get into it really fast.

Considering these information and the fact that in the future I want to have the possibility of continuing Phd studies, maybe not directly after the master studies, but sometimes eventually, which one of the thesis should I choose?

Should I go for the most worldly-renown professor, or for one of the others. Which parameters should I bear in mind when making the decision? I have thought about the quality of the professor, the effort that the topic requires, the potential of having a good adviser (on whom I can rely) etc.

I am sure, here are people much experienced than me who can tell what are the important things to consider when making such a choice.

It seems seems that deep inside, I am being influenced by the grading as well. Is the grade of a thesis more important than the topic itself?

I know the question might feel as offtopic, but I really need help.

Thanks

EDIT 1: Just wanted to add a couple of questions in here; To what extent the grades influence future job &amp; Phd applications?
One thing to keep uppermost in your mind - the topic of your Master's thesis is not necessarily the one that you have to pursue in later research, such as part of a PhD.

The point of a Master's thesis is to demonstrate your ability to do research. Opinions might vary on whether it is a reasonable expectation that the research that you do for a Master's thesis has to be world-class and leads to one or more publications. In my view, it would be nice, but it isn't a requirement.

What you need to get out of your Master's thesis is a strong demonstration that you are capable of academic research. You decision on which supervisor and topic to choose should be guided by this driver. 

Pursuing a research topic merely because the professor is world-renown may be misguided. What happens if you don't strike up a good working relationship and your research falters because of it? Will your professor's reputation outweigh a mediocre research effort?

Your drive and interest in a research topic are strong factors of whether you will succeed. The motivation should come from you - most of the time - to address your research topic. Again, if you aren't particularly interested in the topic, you are going to find it hard to keep going at it when - and it is a matter of when - the going gets tough.

I reiterate that at the end of your Master's thesis, you want to demonstrate your research ability. You are still learning the skills and craft of research, and for that reason, you want to seek teachers who are skilled at teaching how to research. Is it necessarily true that the best practitioners of science research are the best teachers of how to do research? Sometimes true, sometimes not.