For current NFL announcers I second Charles Davis and I also enjoy listening to Collinsworth.
The worst...Brian Griese in a landslide.
Griese is like nails on a chalkboard with his "he said look" crutch. Everyone he talks too says "look" first thing. Not buying it. Even Aikman's "we talked about" crutch isn't as annoying.
Favorite football announcers (all-time):
Summerall/Brookshier
Summerall/Madden
Gifford/Cosell/Meredith
Enberg/Olsen
I liked Scully for football too with pretty much any color man like Hank Stram, Paul Hornung, or George Allen.
Shout out to Bob Starr, Rams radio guy in the 80s
Currently I like Romo, and Sanchez is getting bettter. Also fine with Shlereth and Spielman. Chris Myers sounds robotic but he seems to like the Rams a little so I can tolerate him.
Favorite Baseball (all-time):
Vin Scully/Joe Garagiola
Skip Caray
Favorite Basketball (all-time):
Chick Hearn/Stu Lantz
Dick Stockton with Bill Russell or Hubie Brown.
On the worst ones: Anyone who still slobbers over Tom Brady I just briefly mute or switch channels. Buck doesn't annoy me as much as everyone else. Collinsworth also doesn't annoy me as much as everyone, only when he's wrong I call him "worthless." Beth Mowins is annoying because it always sounds like she chews the inside of her cheek, plus tries too hard to sound like Marv Albert. Albert's Jordan-love hasn't endeared me to him in the past but he's not on my worst list. Just too many "Jordan...............YES!" shouts for my liking.
For old school I never liked Dierdorf on MNF. How could anyone listen to Johnny Most, plus he was a huge Celtics homer. Hot Rod Hundley was also very tough to listen too with that grinding style of his. That old school Whiner's radio guy could get really annoying... my friends and I made fun of the way he purposely dragged his R's when he shouted their team name. On radio Butkus was rough and a huge homer but not annoying. It was funny when his homerism busted through, especially in 1985. That 1999 Rams radio guy was so bad I still cringe when I hear him in any '99 highlights.