I've heard this question come up a lot, sad to say, it's usually when it's too late (meaning if you wanted a basement and you can't get it, now what do you do ...). It is only a potential problem should you want a basement, and can't have one.
You can build a home on a slab w/o a basement if there's too much bedrock to deal with. In this case, just change your building plans to allow for a 1st floor 'junk' room and utility room, or a separate shed/garage for items you normally store in a basement. The existance of boulders on the surface can tell you something either way. If you don't want to have the ground tested by a pro, you'll have to take your chances and become a Geologist, of sorts, for the day. If the lot is part of a morain, then the ground below could be soft. If other homes in the same area don't have basements, then chances are good you can't have one either.
When you talk to your builder, see about plans for a basement. If he hits bedrock at 3', maybe he should forget it. Hopefully, your builder is one that's already built in the area in which your lot exists. His experience with excavating can go a long way. Just talk to your husband about what you'll do if you can't have a basement, and what you'll do if you CAN have a basement. Then, the builder will know what his options are too.