I’ll say pretty much any rendition of the Star Spangled Banner.
M
Actually written by Badfinger.
Sorry, but for the full Rush of nausea you’ve got to go back to the original by Merrilee.
Whether it’s over-the-top bombast or excessive angst, I flip the dial real fast when Bon Jovi’s “Livin’ On A Prayer” comes on the radio.
“We’ve gotta hold on to what we’ve got.
It doesn’t make a difference if we make it or not.”
Couldn’t agree more.
I think it might be a lost cause. Three-quarters of the songs mentioned in this thread don’t fit the OP.
No, no, no. Y’all have missed the best Michael Bolton entry in this category:
My all-time favorite over-the-top Bolton performance. 
John Farnham, You’re The Voice
Actually the albums Whispering Jack and Age of Reason both have a lot of these big ideas expressed in song.
What, no Tom Jones?
My, My, Delilah
Why, why, Delilah
Practically all of Springsteen’s vocals are ridiculously over the top- but they were particularly hilarious in “We Are the World.”
That said, a lot of my favorite songs are over the top. Here’s Ian Gillan of Deep Purple at his best/worst/both.
ACK! That’s what I came here to mention.
I think Clapton’s “Bell Bottom Blues” is a great tune, but when he goes “Do you wanna see me crawl across the floor…Do you wanna see me down on my knees?” and even the chorus (as well as the anguished way he sings it) flirt dangerously with flat-out melodrama.
A low-key kinda melodrama, (in muted tones, say) would qualify Janis Ian’s “At 17” and Streisand’s “People”.
How about a “catchy, upbeat” kind of melodrama with the Supremes’ “Stop in the Name of Love”?
Do we really need to go down the Connie Francis road? Or is she more “maudlin”?
Or how about the most excruciatingly annoying “hearty, fiesty” type of melodrama with 4 Non-Blondes’ “What’s Up?” (“I SAID-A YEAH, YEAH, YEAH X 100…”)
William Shatner’s spoken-word rendition of “Lucy in the Sky With Diamonds” can get a little thespian-y.
“We Don’t Need Another Hero” by Tina Turner
*
It’s all or nothing!*
I agree. It’s OK. I don’t mind if dopers are into posting sappy songs they don’t like.
Oh, if we’re OK on just plain sappy now, I’ll add
“Seasons in the Sun” Terry Jacks (Jacques Brel song schmaltzed to the max by Rod McKuen)
“Billy, Don’t Be a Hero” Paper Lace (also guilty of inflicting “The Night Chicago Died”–the EAST SIDE of Chicago)
“Brandy” Looking Glass
“One Tin Soldier” The Original Caste
Wildfire!
Oh man, I just love over-the-top songs!! This thread is making me grin wider with every song I recognize. Two more that come to mind: “Unbreak My Heart” Toni Braxton and “I Want it That Way” Backstreet Boys.
Or “Stay With Me” which was the B side of the The Rose 45. Yes, I’m old.
STAY WITH ME BABY
I CAN’T GO ON WITHOUT YOU!!
‘Ace of Spades’ by Motorhead!
Does The Band’s “It Makes No Difference” qualify?
Wind of Change, Scorpions: whistling, cheesy music, cheesy video. . .it’s got it all.
I LOVE that song! I’m changing my middle name to Bombastic.
If you’re lucky enough to get tickets to Springsteen On Broadway, I think he does it that way there. The album version fits in with the others, like No Surrender. Someone on the boards mentioned that he likes the Wall of Sound idea and I hadn’t thought of it before, but no wonder I love him like I do the aforementioned “River Deep Mountain High” and similar.
REO Speedwagon and Styx are also contenders.
Sorry, have to present it one more time.
Barth really nailed this version, however.