but for a first horse I think it's important to have an intended direction. Know what you LIKE to do so that you can get a horse that fits that criteria, then if things change we can either train for the new goal with the current horse, or if things work out a different way - sell the horse and get something that does fit what the new goal is.
The important thing is to get a horse that can physically and mentally handle what you're looking to do.
BUT I think a great point you brought up is that if you make a WISE investment in your first horse you are going to be able to sell it and invest in another horse that fits your growing needs. If you make a poor choice you are now going to find yourself in the bad situation of trying to unload that bad decision and it is hard to give horses with issues away...especially if you have any kind of ethical fiber in your body. I would NEVER lie about a horse to move one...BUT people do lie a lot just to get rid of a "problem" horse. So think ahead into the future and know if you make a poor choice it will bite you in the long run even more. It is investment into the next horse in a way...just be careful and use your head instead of your heart!