I know it sounds picky, but a homeowner can certainly be sued in that situation.  Your neighbor is asserting that, in such a suit, the owner would prevail.  And, in most cases, he is correct.  Massachusetts courts have held that a natural accumulation of ice or snow does not create liability for the homeowner if someone slips on the ice.  In one case, Sullivan v. Town of Brookline (416 Mass. 825), the Supreme Judicial Court of Massachusetts went so far as declining to find liability where the landowner had shoveled snow and exposed ice underneath (leading to a slip and an injury).  However, in that same case, the court recognized that a landowner could be liable where his action or inaction creates an unnatural accumulation of ice that causes a slip and injury.  I was trying to think of an example of an "unnatural" accumulation and came up with this:  If you erected in your side or front yard one of those do it yourself ice rinks that you fill with water and you allowed some of the water to run across your driveway and then freeze, that might create some liability. 

In a recent case ( Soederberg v. Concord Greene Condominium Association, Appeals CourtNo. 09-P-380, February 25, 2010) a Massachusetts appeal court emphasize the point that, with any unnatural accumulation of ice or snow, the property owner may be held liable for injury, EVEN if the hazard created by the unnatural accumulation is obvious.

Regardless, let's play it safe and use a lot of sand and salt this winter. 

UPDATE:  MA SJC throws out the old rule discussed above regarding the distinction between natural and unnatural accumulation of snow or ice.