I've done this twice, and though it wasn't as much as irreplacable as a PSP. I've lost a pack of CDs on one flight, and then a month later, a CD player. In neither case did I get them returned, but because AerArann is much smaller than Untied or American, you'll have better luck.
But now, I put address labels on things that I might slip into a seat pocket, and always try to remember to check the area around me for personal belongings.
good luck.