since I work at gamestop i can tell you how its going to work there.. at gamestop elemental has a ship date, not a street date. a ship date means exactly that, on release day the game will ship to gamestop and normally arrive the following day as we have over night shipping with most vendors.. a few take 2 days.. (so games in stores on 8/25/10 in most cases) conversely Starcraft 2 had a street date at gamestop so we got the games on the Friday/ Monday (shipped from vendor Thursday 8/22 or Friday 8/23 so was in store for our Monday midnight release (i.e. Tuesday 12:01 am est arrived fr before the release date)).
now if you buy the game from a vendor that ships it depends on the vendor.. since game has release date of Tuesday 8/24 if you pay overnight shipping and order from stardock, you should get it on Wednesday 8/25 other vendors even with over night might be on 8/26 unless stardock has set up drop ship which means still 8/25 with over night shipping (at least that's the hard copy digital download is typically available 12:01am of release date.)
unless stardock has special plans (and I have seen no information on this) I expect it will go as i have described..