Ok, then to my opinion.

I mostly fly within Europe. My main goal always is to reach my destination at the right time, as quickly as possible and with the least of effort. Therefore
I would list the factors for my decision as follows:
1) Time of flight
2) Number of stop-over
3) In case there has to be a stop-over, the airport of the stop-over
4) Efficiency and at check-in, boarding, etc. (basically just has to be quick and at least a little bit friendly)
5) Aircraft (don't really care about the age of the plane or the neatness of the interior, but about legroom)
6) Loyalty program

I would never choose an European flight because they serve a meal on-board. However when I am on the flight it still upsets me if you don’t get anything, but it makes me mad when they give you one of this tiny sweets just before landing. When I am staying in a hotel that does not serve breakfast, lunch or dinner I don't need the chocolate on the pillow either.

The price of the flight is not a factor on a business trip for me, as I don't have to pay for it. That said however, the decision which flight to take is not always solely mine. In that case the factor of the price would propably rank as number two.