So I have been nominated for a promotion

How did this happen? I came to work this morning, took my laptop off hibernate and continued watching girls dance tick tock on youtube from where I left off yesterday at quitting time. Shortly after a head of department (HOD) of another line of business within my company called me and started asking me about my current level within the company, he then told me of a vacancy of a higher level position with direct reporting to him and said I should apply for it as he thought I would be a shoo-in for it and he thought very highly of me. what??
I remember once working on one of this man's servers and fully corrupting his system partition resulting in his server being down for the remainder of the business day. At the close of that business day he called me and asked what was going on at which point I took full responsibility of the damage(against the advice of other people who said I shouldn't) and explained to him the causes and he congratulated me for not trying to cast the blame elsewhere as most people would :-) I guess honesty does pay off in the end as this HOD wants me to under him.
He had to rush off to a meeting so he just sent me a copy of the job description so I can go over it said he would call me back later to give me more details. I now have time to stew and make a decision.. this was turning out to be a very hard decision as I love my current job and a promotion doesnt necessarily equate to more money as I earn a lot of extra money via standby duty currently which wasn't part of that new job.
Enter my supervisor: The big twist, well not big but interesting
As I typed this post he came over to my desk and asked if I heard anything from HR about job movements.. this confused me greatly. The conversation continued on like this.. in essence:
me: nope, why?
sup: oh they were supposed to send you a letter about job movements
me, still confused: whats that about, that other HOD called me about working for him.
sup: oh he did? well HR is supposed to contact you about a pay increase, you are now at that same level as the job he is offering.
me: [some other random garbage said in aww after recieving this new information]

I guess that answers that question, stay where I am and get a promotion anyway. It is funny my supervisor quickly told me this after he realized the other HOD was shopping around for someone.. hey I'm not complaining though :-)

FYI: