Excuse is the wrong word to use. None of us have to 'excuse' our conduct unless by purchasing another air rifle/motor cycle/fishing gear/cameras/lenses etc, they prejudice the finances of their families. The word that best describes that sort of person is 'idiot'.
Moving on, air rifles are very like cameras in my mind. Provided you can easily afford it the ideal is to have a different rifles for different purposes. Precharge backed up by self contained and so on. Also my choice is very different if I have a FAC or not.
If all my shooting gear was stolen or destroyed I think I would like the following air rifles..
1. FAC precharged hunting rifle-almost certainly a .25 regulated Rapid.
2. Back up FAC hunting self contained rifle-a .22 HW80.
3.Club/competition .177 precharge-choice is very wide.
4.Club/competition self contained-probably a .177 tuned HW97 or AA TX something like that.

If I didn't have a FAC I think I would pick a .20 Rapid/HW80 back up for hunting and the same .177 target rifles as detailed above.

Only one rifle? Really difficult and I'm glad I don't have to limit myself in that way.
If I did? OK, .20 HW80.