I agree, those are some awesome announcers.
My best announcer ever is Jeff Steitzer from the Halo series.
Fantastic announcer plus medals equaled great sense of accomplishment, enhancing the gameplay.
The announcers from MadWorld were rather funny, turning what would be a mediocre game into one that's actually playable.
The best announcer from that line up would definitely be the Unreal Tournament guy though, he made every kill better.
Shao Kahn baby will eat your soul.
I almost creamed myself when I first heard the UT announcer. And it's been in so many games since. It just doesn't get old. Clearly the best ever. Though I do also have a soft spot for the TF2 announcer, as it is amazing. Additionally, the Bastion and Pyrion Flax announcer packs for dota 2 also rank up there.