On the 747s, 19A is the seat I always fight for (probably shouldn't be saying that).. why?
It's the closest to the front door and you can often be the very first person off. It's near the coat cupboard so if you had a jacket hung up, you can get it quicker. You don't have to pass anyone to get to the nearest toilet but it's not right on top of you. You don't have anyone sat behind you. You have the furthest distance between you and the person opposite as is possible on any Virgin flight (in my experience).. it's perfect if you want to be as secluded as possible without being on top of someone else (e.g. 1A/1K or the far end of the nose).
As a solo traveller, I challenge anyone to come up with a rationale for any other seat being better
