I just flew Aer Lingus this past Christmas 2006. We flew Manchester-Dublin-NYC/JFK.
Overall, our experience was totally fine - and even better since we only paid £300 return each.
On the way out our plane was bare bones - a television in the centre ceiling every few rows and the food looked average (I never eat airline food). However, on the way BACK to the UK our plane was fantastic! It was nice and new and it DID have seat back entertainment televisions, each with a remote control. My husband was in heaven (movies, tv shows, music, and retro video games). Maybe you could find out in advance what type of plane you'll be on - you may not have to bother with a dvd player.
There are just two things about the trip I need to mention that were negatives:
1. Dublin airport can be very confusing. When we arrived (both times) you have to go through customs and baggage claim and completely depart the airport (you pass by family and friends who are meeting passengers). Then you have to go BACK into the check-in area. If you have your continuing ticket (which we got in Manchester) you go through a 'fast-track' system and bypass security to your gate. If you do NOT have your continuing ticket (which we did NOT get in NYC) then you have to wait in line AGAIN and go through security and re-check in. It was absolute chaos and I don't have children! Everyone else here seems to have had a better situation then me!
2. When we flew over we had no problems (Manchester-Dublin-NYC). However, when we flew back, I checked online for the flight status and was alarmed when it said a time for landing in Shannon. Shannon?!?! I phoned the airline and they said "oh yes, there is a stop in Shannon, but you do not get off the plane unless it is your final destination". I was extremely annoyed - at no point whatsoever in my booking did they mention a stop in Shannon. Apparently since it said 'direct' flight and not 'non-stop' flight, that means they can stop off somewhere for some people to get off but not inform you when you are purchasing your ticket. So in the end we had to fly NYC-Shannon-Dublin-Manchester. It was very frustrating, so you may want to check if your plane will make an additional stop.
But all-in-all, for £300 return, I'd do it all over again next Christmas!
I hope this helps! Have a wonderful trip and safe travels!