It's really close to a tie, but I have to go with the Birds by a hair.

By far. The Birds is ok, but Rear Window is awesome!

My vote is The Birds as Rear Window really irates me.
The best part of Rear Window was Thelma Ritter -this lady was a fantastic character actress and the scenes where the woman in the opposite building puts her doggie in a basket and decends him out of the window to do his poos,lol.

I love The Birds, but Rear Window was far superior. It's truly a masterpiece!

A close tie...

Rear Window is one of the most intriguing movies of all time... it is soo brilliantly made and the story was incredible.
Grace Kelly and James Stewart WOW they really do pop together dont they... almost as good as the irrefutable on screen chemistry of Grace and Cary Grant :D

Grace Kelly is lovely and Jimmy Stewart is wholesome, but the combo doesn't gel with me...She is too "unreal" and he shouts too much. Never really cared for either of them. I agree that Thelma Ritter really made the movie, she was so down-to-earth. I definately enjoy watching the Birds much more then Rear Window.
The effect of watching the Birds is much more suspenseful then Rear Window anyday.

Rear Window has a lot of artistic aspects (relationship, sense of self, incredible climax, light/dark sequencing). The Birds was very well done but seems to be a much more simpler recipe.

Such a classic! Been copied so many times ever since it's release!

I love both, but I think the pacing is better in Rear Window.