Hey Dave,
I've built a few homes myself so i can probably offer some advice - i hope. I'm not sure your long term plans.. but no matter what, in my opinion you have to look at building a home as an investment. Most people move several times throughout life these days so whenever I have built a home I try and think about resale. That being said, choosing a lot is pretty important. Location is a big deal in real estate so try and find something that is close to schools, good neighborhood and will have good resale value.
As related to construction, i would try and get a lot without a great deal of slope to it. Sloping lots can be much more expensive to build on because of soil rentention, engineering and increased construction costs as a result of the engineering. Plus, you usually have to do extra retention just to make the lot usuable for your family. If the best lot you find is a sloped lot, try and find a plan that has a walk out basement or a plan that is meant for a sloped lot. However, again you have to think about resale, so if you find a great floor plan that isn't necessarily designed for a sloped lot already - purchase the CAD file and have a local draftsman make the necessary modifications to accomodate the lot.
As far as building yourself vs. using a contractor... You can save some money if you do things yourself, but consider a couple of things.
1. When a subcontractor give a builder a bid, he is more agressive with him that he would be with you because he could potentially have many more jobs from that builder - not likely with a homeowner-builder. Having worked in construction and speaking with subcontractors about their experiences, I know this is the case more often than not. So you may save the general contractor's fee, but actually spend more for all the subs that charge you more than they would the builder.
2. Sometimes your inexperience will cost you more - Example: An neighbor owner builder asked his excavator to dig his hole a certain depth, unfortuantely, it was several feet too deep for the plan he was doing. In the end they spent quite a bit of money bringing compactable soil back into the hole before they could set the footings.
3. Can you handle the stress doing something you are unfamiliar with? If you are in the construction industry already, you can generally save money building your own home. If you are not... you may want to work some overtime at your day job, or pick up a second job to help pay someone who does have experience.
I don't mean to discourage you, but give you some pointers that may help you make a decision. I have seen a lot of people build their own home and save money... and others who end up spending more with an incredible amount of stress. if you do decide to go with a contractor, i would get some references and speak with people he has built for before making a decision.
I hope that helps.