Bethesda is first for me. A new Fallout means I'll be very interested and Rage 2 looks good. If Starfield is announced, and is actually a "Fallout in space", then they'll have won without question.
Sony is second, mainly because I really want to see more of Ghost of Tsushima.
Microsoft is third, mostly because I can play most of their games on PC.
Ubisoft can be hit or miss, I have no idea. Their "train wreck" conferences can be gruesomely entertaining, though.
I'm not really interested in EA, Activision, or Nintendo, not unless they pull out a surprise.
Borderlands 3 isn't supposed to be a E3 but if that's a smokescreen then it could change my priorities significantly.