Will Ferrell's Carey is better than Carey was himself.

Let's not forget the great Dizzy Dean "Zernial slud into third"

or when Mccarver said "Hey look at all the seamen in the upper deck" at a Padre game

What does it take to be announcer? College major? Open tryouts? Just being famous?

Jon Miller is terrific. Unfortunately, he and Joe Morgan didn't have great chemistry on Sunday Night Baseball. Eric Nadel (Rangers radio) is really good; so is Josh Lewin (now Mets radio). Some of my earliest memories were listening to Harry Caray and Jack Buck on the Cardinals broadcasts in the 60's. Caray was really good back then.

Costas is not a very good game announcer, I agree. He is very good at times when he has a stand-alone commentary program or special. And his eulogies of Stan Musial and Mickey Mantle rank with Pericles' Funeral Oration  - you can find them on YouTube easily. 

Gowdy was not only a very good baseball announcer, but almost forgotten now, but might have been the best football announcer ever. Some of that sports' greatest moments bear his stamp:

https://www.youtube.com/watch?v=qmkOp8WlCsY

https://www.youtube.com/watch?v=GMuUBZ_DAeM

RIP Kenny Stabler

Haven't looked here in a while,,great, fun responses from people older and younger than me,,does my perspective some good.

Agreed, rip snake, a great player, great character,and one of the funnest,,,(correct English, IT?) players, on an eclectic, yet very good team.,,,who has a lefty qb these days??

To me;
the good:
Vin, less is usually more, and better
Costas, a supremely calming influence, like listening to my uncle,,,wisdom and knowledge..
Jon Miller, el voce
Al Michaels, anything can happen
Jack Buck,,,nuffced

Caveat, wont include any mostly regional, or specific team guys,,not enough ammo.

the less good:
they are mostly ex ballplayers,,,

The more I watch/hear Costas, the more I despise him as an announcer.  Every game he gets critical of a play, and he is gently corrected by his partner as to why what the player did was correct.  Or, he uses the wrong terminology: just last night he referred to a weak hit to right as a corkscrew, which it wasn't - duck snort, bloop, dying swan, etc., but the ball wasn't hit off the end of the bat and didn't have any spin.  No, it wasn't a case of making a quick assessment of the situation: it was during the REPLAY.  And when he starts pontificating, I reach for the mute.

Somewhere along the line I overlooked Dick Enberg - not the greatest but very, very good.  The consummate professional behind the mike.

decent point, costas has never been a snap analyst of the game, but his demeanor is worth it to my generation

Fair enough!  There has definitely been a demarcation line roughly drawn by age.  We old-timers love the soothing baritone of Vin Scully - don't startle us! - whereas it's been commented here by a young whippersnapper that he just prefers more animation in his announcers.

as far as former players,,,

jerry remy, funny, and sometimes unprofessional, in a boston way
garagiola,,,cool
mccarver,,,know it all,,not
I hear Kenny singleton is good

never listened to the old classics (reese, kiner, dizzy, ) just smatterings of phil riz, liked him as a goofball

some former players on mlb network are very well-spoken, and insightful(doug Glanville and kevin millar, come to mind, not to mention pedro, and schilling, when they are on

a good point, slott, but its not about demarcations,we learn from our elders,,(if they deserve it),, and educate the next generation,,(same,,lol)