The install disc is indeed nearly 8 GB as of now.
The install takes around the same amount of space now - with none of the upgrades probably being less than 200 mb, and with a few additional languages added to installation discs, and not excludeable from the updates, just like the included languages until now.
Compared to 4.6 GB for 10.4, under 3 GB for 10.3 and 1.x GB for 10.2 and before, and less than a CD for 9.x and before.