How you want your barn depends on a lot of things! I've been in the horse business for 30 years and my husband builds barns. It depends on where you are on this planet...what country, what state...the weather does have an impact on your decision. It depends on what the intended use. How many horses. The property characteristics, your budget, the style of horse manangement, storage (what, where), equipment, and on and on.
I don't know how much experience you have with horses or caring for them. If you have lots of experience that is good. If not, get someone with lots to help. Better to have a builder that has horses or is married to horses. Lots of builders can build you a pretty barn. Pretty is very nice, functional is better. One that will hold up to horses wear and tear and is designed to make your life simpler is better than pretty.
Take your time during this planning stage. Consider not just your needs now. But what they might be in the future. What if you want/need to sell later. What if right now you use bagged shavings, but 2 years from now you need to use bulk saw dust, or what if now you use small bales of hay but next year hay prices sky rocket and you need to get large bales for awhile.
Take your time with the planning stage.
Lots to think about! But it is fun! I've designed several barns for my husband's clients. I love doing it! It is the only time my husband and I can work together. He gets it since he is married to a horse business and helps out around the farm. So the planning part is important to him to get it right. Esp after living in barns that weren't planned well.
Did I mention to take your time with the planning?
Take pictures of the whole process from what your place looked like before through completion. It's fun to look back at the pictures. We usually do a picture story book that we give to all of our clients at completion. They really enjoy them.
I wish you luck! Have Fun! Find the right support people to surround yourself with and you will be fine!