You should go and ask them please to be quiet. I did this on what I call the "reverse red eye" last year. It's from EWR to SFO and departs at 8:20PM. With the ATC, it's in the air by 9:30 or so. I like it because it's late enough that I can actually sleep on it and feel somewhat refreshed the next day.

I was in F at the bulkhead on this flight in summer '06. I was awakened from my slumber by the post-service banter. After a few, I got up and asked them to pipe down. They did, for a while. Then I had to ask again. This time they got the point that I'd report the problem if it didn't stop. It did.

This is one area where NW is an improvement. There is only 1 FA in FC n NW flights, even on a 757. So, when s/he is done with the service, they just sit and read...there's no one to talk to.