I always used to think that the writer Harold Pinter most resembled was not Beckett but Noel Coward. Pinter's famous dialogue, with its clipped phrases and constant suggestion of something deeper beneath the surface (even if we're not really sure what that something is supposed to be), put me in mind of Coward, who did the same thing in all his plays, and even summed up his own method with a line from Tonight at 8:30: "Small talk, a lot of small talk, with other things going on underneath."
However, I note that Pinter never claimed much influence from Coward, though he professed to admire him and even directed Blithe Spirit once -- a production that doesn't sound like it was a barrel of laughs.
Alicublog has an amusing roundup of angry, politicized, generally Philistine reactions to Pinter's Nobel Prize from such Powerline-quoting, art-hating dolts as Roger Kimball. (For the uninitiated, Kimball is like a slightly better-read Mark Steyn.) This is an annual tradition, except for the time V.S. Naipaul won, but it's trickier with Pinter, because the work that made his reputation is not openly political, while his political stuff is not considered by anyone, left or right, to be his best work. Therefore the Kimballs cannot use the usual New Criterion method of critiquing a writer whose politics you don't like, which is to write three pages of plot summary followed by one page of explaining that the work is bad because it is "too political," meaning not political enough in your favored direction. Instead they have to skip or gloss over the work that made the writer's reputation, and say that the work is not even worth discussing because he's written some annoying articles in the last couple of years. Sort of a throwback to those Stalinist critics who used to dismiss writers on the basis of Bourgeois Decadence, only it's now the critics of the political right who want to bring down the left-wing Bourgeoisie.
That said, I'm not the biggest Pinter fan, just as I'm not the biggest Noel Coward fan -- both writers are skilled writers of dialogue whose plays are entertaining but tonally limited. Still, on the theory that an important criterion for the Nobel Prize is influence, Pinter is as good a choice as any, given that his influence on British play writing was largely positive, helping to free it from the extremes of Good Taste on the one hand and kitchen-sink bellowing on the other. Plus one of his plays, Betrayal, inspired a Seinfeld episode. That's Nobel stuff right there.