OK, no flaming, huh?
Ayukat's post indicates that he has not thought this out carefully,
and the fact that he has yet to perform his service serves to
further emphasise the baselessness of his opinions.
Speaking from the perspective of a person who has spent ten years
in an environment where national service does not exist
(Australia), I can clearly see what I personally got out of
national service. Perhaps my experience in 1 CDO is unusual, or so
my friends from other units keep telling me, but nonetheless it is
an example of what a national serviceman can take away from his
experience.
First and foremost, NS provided me with an environment in which I
could develop a work ethic, which was something that I did not
experience in school. The tasks that we had to perform had an
element of reality to them that academia could never hope to
imitate, and that provided a sense of purpose for developing said
work ethic. I did more and did it more thoroughly than my
classmates at university. At work after graduation, this work ethic
has also served me very well.
Second, having performed some rather challenging tasks in the
course of duty, I walked out of the army a sense of confidence that
I could deal with any situation. While my university classmates
were running around like headless chickens at crunch time, I was
already accustomed to making sure I stayed calm so that I could do
the job right. Again, at work, this was a great help in giving my
employers and clients a strong sense of confidence in my
abilities.
As a spin-off of the confidence I developed, I also learned to stop
running around trying to prove something, only to find that I
didn't know what I was trying to prove and who I was trying to
prove it to. While many of my classmates were wasting a whole lot
of time and energy with grandiose but effectively useless projects,
I made every move count. When I was supervising Honours students
completing their theses, the first thing I would teach them was the
concept of mission requirement, so that they didn't waste the ten
short months they had to produce their theses. Of all of my
students, only one student went as low as a lower second-class -
she was too set in her ways to grasp the concept. As for the rest,
they have all gone on to employ the mission requirement concept in
everything they have done subsequently. Applying the concept to my
own thesis, I currently hold the department record for producing a
30,000-word thesis: 8 months out of the 3-year allocation.
In the course of teaching, I also adapted the military method of
instruction and communication to my needs - this helped me to
ensure that I got the message through clearly to my students, and
in later years, to my clients and colleagues.
When I was working as a human resources consultant, my military
background helped a lot - the field of human resources grew out of
the military during WW1, and the industry's enchantment with the
military remains very strong today. Of course, "1st Battalion,
Singapore Armed Forces Commandos" makes one hell of a brand name!

At the end of the day, the skills and working principles I picked
up during NS, with subsequent development and enhancement, have
been a great help in tucking the competition away.
This has all come from one very simple decision: "I'm stuck here
for the next two and a half years, like it or not. I may as well
get as much as I can out of it".