You need to be more precise about your breeding goals.
In general it is always safer to start with fillies/mares, IMHO. There are always plenty of good stallions out there and their owners have spent alot of $$ testing them, promoting them, showing them, etc.
While the colt looks lovely, it takes a very experienced person to predict accurately the weanling foal who will grow up to be a solid stallion prospect.
I agree on knowing your breeding goals and knowing what will do well in the future. Breeding without a specific goal and potential customer is a risky venture. Knowing what will do well and having the proven pedigree behind it are all important.