When I made my girls' baby quilts, I made them big because I hoped they would use them on their toddler beds. They're 3 and 5yo now and they both still love their baby quilts best. They're about 56 x 66 which tucks nicely under the foot of the bed (little kids are crazy sleepers) but still enough length to fold down the top portion and tuck securely around them at night.
Whatever size you choose, I'm sure the recipients will love them!