As much I love "Alias", there are a few sets that I just see over and over.
The most recycled set (that I can remember) is a dark passageway with a big pipe running beside it. I believe it was in "The Telling" as well as in Season 4 when they are trying to infect the water supply. There are many more as well, but i cant remember them right now.
The second would be the "White Stairs" which are in the beginning of "Facade" and also i remember Sark shooting Vaughn in a vest (i think season 2) and Sydney going to help him. Again, i think there are a few more times it was used.
Any more anyone can think of?