I posted this on the www.diychatroom.com also:

There are many variables when it comes to a cost of having a window installed.

Window:
Type of window (DH,Awn,Casement,etc)
Glass package ( Double pane,Triple Pane,Heat Mirror,etc)
Window Options (Grids,Decorative glass,Woodgrain interior,Color, Foam Filled Frame,etc)
Company :
Size of Company
Do they have Sub Contractors or employees for there installations?
Do they advertise?
Do they have all the necessary licenses?
Do they carry Workman's Comp on there employees?
Do they offer a Labor warranty?
How Long in Business?

Installation:
Type of window removing?(Metal,Wood,Vinyl)
Replacing any Interior Molding
Painting or Staining of interior molding
Replacing any rotted wood
Capping existing outside casings
Removing all debris from job

You see there are a lot of variables on coming up with just one set price for an installation of a window. Every company is set up differently and price will vary. I myself would not use a company that hires sub-contractors for there installation. Most subs are paid per window and only naturally they might rush the install ( not all do). If you do hire a company that uses subs make sure you request looking at a few jobs in your area and request the crew that did them.
There is a lot more I could list but the main thing is to check the company out. Go look at a few jobs they did, call there references, make sure you get everything in writing!
For the final contract I would ask:

*Exact brand, model, and options for each window in writing
*Exact sizes
*Approx lead time and install date
*Method of install, approx # days/hours to install
*Any included exterior wrapping of windows
*Any interior trim replacement required,
*Who is responsible for Staining or Painting of Interior Trim.
*Who is in charge of debris removal/cleaning, disposal of old windows
*What kind of Insulation they use to seal around window(Fiberglass or Low Expansion Foam)
If they offer a warranty on there work make sure you get it in writing on the contract! Also if they say they do not charge for Service Repairs get that in writing also.
Hopefully this helps you a little

Nice Post needwindows! I must of missed it at the DIY site. Off topic but I own www.weneedwindows.com.

To the original poster:

The pick up truck guys sell windows for $200-$400 each installed.

Most mid-range companies charge $400-$600 each installed.

Most high end companies charge $500-$1000 each installed.

Some expensive companies charge well over $1000 each installed.

I replace $200-$500 window jobs all of the time. Low price products, cheap labor and out of business companies keep me busy. It better to pay more up front for a great company that uses a great product and an excellent installation team. A company has to make a profit in order for them to be around in 10-15-20 years to service your windows.

The link that I provided you in another thread is for you so you can see how the windows compare.

Last post. Great imput. I have sold for many companies. Corporations, franchises, and family owned. I would always go with a bigger family owned company. you will get better service and bang for your buck. $400- $600 should get you a good window with good installers.