A couple of good older books:
The right dog for you by Daniel Tortora PH.D
and The complete Dog buyers guide by
T.F.H. publications are pretty informative.

There is a web site that compares
dogs. It might be put out by Pedigree?
Maybe someone on this site might know
the web addy. AKC has a good site on the web also.
Once you narrow your choices down its a good idea to visit a dog show and see all
the breeds you like and talk the the breeders. If they are not busy they
are usually happy to answer questions.

Also write to the official breed clubs.
(some of the breed clubs have web sites also) Most breed clubs have a packet of information on their breeds, which will state pro's and con's.

Have fun in your search and when the
time comes share your choices.