My SSD died the other day, & I got a smaller one forgetting that a W7 system restore image won't go onto a smaller drive. (Same issue if you use Clonezilla.) Anyway, I had to do a full install of W7 and the size of the updates was massive. Firstly about 700 mb. Then there was one about 200 mb. It kept going on until there must have been well over 1 gb in total. It took two or three hours at least and countless reboots.

On the plus side all the updates came through super fast, even the first 700 mb one.

From what I have read MS have been quite open about this, they have told people to expect the monthly rollups for W7 to get bigger and bigger, as they incorporate previous updates.