Hello Eager and thanks for your post.
As the others have already noted, the price of the home located at 1684 Via Campagna in San Jose is just about market, so there is some room for negotiation. You should check the school district with Campbell and Los Gatos to ensure that the home is, indeed, located in the Campbell School district. Districts will occasionally split a street in half, so it is conceivable that one half of the street is located in the Los Gatos School District, while the other half is in Campbell. Both are good school districts, on the whole.
However, regarding the landfill, I'm not concerned about the landfill and, if this is one of your bigger concerns, you might consider this just about closed with the City of San Jose. According to San Jose's own records, the Guadalupe landfill is scheduled to close sometime in 2010. The site is almost at is 16,000,000 ton capacity, and is slated to close by the end of 2010, if not early 2011. Federal and State laws require that trash be encapsulated daily with a fresh layer of dirt, which minimizes smell and promotes degradation of the material beneath. Landfill technology is quite awesome, and there are plans in place to address both the methane gas that comes from the landfill as well as the rainwater that might soak into the material. Once closed, the landfill operators are required to "cap" the material to prevent gas problems, smell and water intrusion--so all you will likely see after the landfill is closed is vegetation and, perhaps, even a golf course or open space area. Landfills are--by law--monitored for 30 years after closing, so any ground water contamination and/or hazards created by a landfill are quickly removed.
So, I think I can safely say that the landfill problem should not be a problem very shortly. As someone who worked very close to a landfill for years, and then for a period after it was capped, the area afterwards was turned into parklands, contributes well to the community and is now the home of the Shoreline Amphitheatre in Mountain View. On a more "green" note, gas generated from these landfills is often turned into electricity that is added back to the electrical grid.
Good luck and let us know if you need any additional information.
Grace Morioka, SRES, e-Pro
Area Pro Realty
San Jose, CA