My wife and I just returned from a trip to London, Florence, Lake Como and Milan and I have to tell you that all three airlines we used were really great. We used Icelandair to go from Boston to Reykjavik to London, British Air from London city airport to Florence and Aer Lingus from Milan to Dublin to Boston. All five flights left and arrived ontime, the checkin process was fast and easy and the inflight crews were all fantastic. I would highly recommend any of these airlines if you're looking for flights to, in and from Europe.
I recently went to Italy from Boston on Aer Lingus and I agree the service was great. On the Atlantic legs we were served a snack and drink, a dinner and a light breakfast. Another bonus was we went through US customs in Dublin which went quite quickly.
I've always had good service in terms of departure/arrival times with Icelandair. That plus their inexpensive fares makes them my go-to choice for travel to Europe.
I would add TAP the Portugal national airline to this list. For a short flight apparently they were not able to provide inflight service but they gave us a 6 Euro voucher to use in the airport which was a nice touch. My positive thoughts about TAP may also be a reflection of loving Portugal in general - so take my review in that context.