Number of Lines into House?

Hello--

Need some advice on set-up, please.  We're moving into a new house where the contractor is putting the coaxial lines in the baseboard and running them all into the basement to keep things as clean as possible.  I'll have an HD DVR+ and two HD boxes in the house.  How many seperate coaxial lines need to be run?  Does each TV need a separate line to run to the basement or can they all be carried on the same ones etc?  I know the HD DVR needs two.

Thanks--a novice at all this.