Deus Ex: Game of the Year Edition

Save Location
Steam\SteamApps\Common\Deus Ex\Save

If playing Revision you also need to check: Steam\steamapps\common\Deus Ex\Revision\Save

And if enabling Biomod also check: Steam\steamapps\common\Deus Ex\Revision\BiomodSave

You can have a few hundred megabytes of saves in the default Deus Ex\Save folder, yet have tens of gigabytes of saves in the other two due to the increased texture sizes.