I prefer an oversized ring, expecially if you are planning on putting a dressage fence in it. Our ring is 80x200 and it makes it easy to have people lunging and riding, or young horses, or a bunch of horses.
If you can go bigger, I would. Then you can also fit jumping courses in easier.. just in general more room is better. And with 14' aisles people can also bring in tack trunks. We just have stalls down one side of the aisle and we hang blankets and everything on the empty side of the aisle, makes life easier than trying to fold wet blankets and hang them for sure.
They say money doesn't buy happiness -- well happiness doesn't buy horses!