I make my own wine and give as gifts to friends and family. The 4x5" labels have worked out so well for the labels! Not sure what is more fun, making the wine or coming up with the funny label designs!
If you can get wine bottles that are not tapered (like 4th over from the left) then they work out better. The tapering makes the labels bunch/crinkle a bit. I use what ever bottles I can get my hands on tho, beggars can't be choosers!