When it comes to roofing across the country, you have many options.  Below is a list of roofing contractors who can handle the entire US with commercial roofing and residential roofing options.  

Clearfork Roofing Co. - Abilene area
Roofing Buffalo NY - dot net site
Roofing El Paso - another dot net site
Roofing Toronto Area - for Canada
Roofing Columbus - for the mid west
Baton Rouge Roofing - dot org site, Louisiana

It is better to get a roofer that handles work himself and not people who are employed on a wage. When you have people on paid, there are higher overheads and disgruntled workers who don't care about the work because they feel they are underpaid. Also companies that employ workers will go for the cheaper option and get apprentices who really need time to learn the trade where as licensed contractors have the knowledge and experience to complete the work. Never pay down a deposit until materials are delivered, under any circumstances.  This can lead to you losing money.

A mid range sales quote on a new roof is usually what you want to look for.  Call any of the contractors above to get a better idea of the services offered.
 
Also, your new home doesn't stop with just roofing.  Make sure your home has proper insulation and radiant barrier installed.  A vent to allow heat to escape in the summer is also a great idea and can be closed off in the winter when you want to keep your attic and roof as warm as possible.  Also, keep snow off your roof as this can damage shingles and lead to costly repairs.  For more tips on productivity, visit the Toilet Paper Entrepreneur.