AM/FM Characterization: Bumblebee, the first Transformer our protagonist meets, actually has no real voice capabilities, and instead does all of his vocalizations through playing songs on his stereo. This is the trope cranked Up to Eleven.
Bros Before Hoes: Inverted; Sam's friend reminds him of the trope, but he's kicked to the curb so Sam can go after Mikaela.
A rather different case than usual — most of the Autobots turn into cars, who apparently know Kung Fu. For the first movie, in fact, Michael Bay instructed the animators to watch Kung Fu movies to get a feel for how they should move. According to the DVD extras, he even had martial artists on wire rigs filmed to visualize the combat movements of the Transformers in hand-to-hand combat.
A more traditional case was Bumblebee's slide/drift in vehicle mode to knock down Barricade while rescuing Sam and Mikaela.
Car Skiing: Bumblebee does this to scan and transform into the 2009 version of the Camaro.
Chekhov's Gun: Optimus outlines a plan that the only way to destroy the AllSpark is by merging it with his own spark in his chest. The idea was that eliminating the AllSpark and Optimus along with it is preferable over Megatron getting it. Sam managing to execute that plan on Megatron was definitely seen as a Million to One Chance.
Chest Blaster: Blackout's chest cannon, Frenzy's CD blade launcher.
Dawson Casting: Shia LaBeouf was 19-20 while filming and Megan Fox was 19, both playing high school juniors. Bay mentioned that he was initially not interested in LaBeouf because in his movies immediately prior he had grown a goatee, making him look too old to play a teenager. Seeing him clean shaven convinced him otherwise.
E.T. Gave Us Wi-Fi: The Decepticons' ability to infiltrate Earth technology is Hand Waved by stating that all modern tech was reverse-engineered from the captured Megatron, which would also explain why the AllSpark could be used to transform Earth's tech.
The film had its fair share of gruesome deaths. Bonecrusher and Frenzy both getting beheaded (in Frenzy's case, by his own weapon), and just look at the mess of what was formerly Megatron's chest after the Allspark is rammed directly into his spark.
How bout that soldier in Lennox's squad in the who got impaled in his chest by Scorponok?
And Jazz's death.
Jazz: "You want a piece of me? You want a piece?!"
Megatron: "No! I want-" *tears Jazz in half* "TWO!"
Freeze-Frame Bonus: When he tries to attack Sam, Barricade disguises itself as a police car, with "To Punish And Enslave" written at the side (instead of "To Protect And Serve").
Hidden in Plain Sight: Parodied when Sam asked the Autobots to back off from the house while he searched for the glasses. The Autobots transform into their vehicle modes... and sit right there in the back yard. Sam screams at them that it's not a truck-stop, and they have to hide in robot-mode. Optimus later invokes the trope in his message before the credits.
Hollywood Hacking: The entirety of the slightly-less-than-awesome "signal processing" subplot.
Humans Are Bastards: The capture of Bumblebee by Sector 7, which, coupled with them repeatedly blasting him with freezing chemical during and after the capture, has a definite feeling of torture. When Bumblebee almost shoots the engineers after they release him, it's hard to blame him.
Some of this is even intercut with the rest of the Autobots questioning Optimus over why they should save us from the Decepticons, given how primitive and violent we are as a race. Optimus Prime reminds them that at one time, Cybertronians were Not So Different from us.
Ratchet is one of the physically strongest Autobots. He's also one of the slowest.
Ironhide even more so.
Mistaken for Masturbating: Sam Witwicky's parents notice that he's hiding something from them. Sam's mother outright asks if he's masturbating, and his parents proceed to try to give him space.
Moment Killer: Invoked by Mikaela. Sam's parents were questioning Sam's nervous and twitchy behavior (due to the Autobots hanging out in the backyard) after coming into his room, with her trying to hide. To end the conversation Mikaela presents herself, making it seem that Sam was acting that way because they interrupted an intimate moment. Rather than being upset, Mom and Dad Witwicky are thrilled for Sam.
Judy Witwicky: Oh my gosh you're gorgeous! I'm sorry you had to hear our little "family discussion."
Ratchet's introductory comment: "The boy's pheromone levels suggest that he wants to mate with the female."
Earlier, when Bumblebee pretends to cut out at a local make-out point, his radio starts playing Marvin Gaye's "Sexual Healing".
No Conservation Of Mass: Mostly averted, since care was taken so that the Transformers had the same amount of mass in vehicle and robot form. However, the Cube can apparently go from house-sized to basketball-sized with no release of energy. That said, the Cube is a magical MacGuffin responsible for the creation of a not just a race of transforming giant sentient machines but their entire world as well so it gets a little leeway.
"Not Making This Up" Disclaimer: Michael Bay mentioned in the DVD Commentary that the sequence where Lennox had to deal with an obnoxious telephone operator to get a call transferred to the Pentagon while under fire was taken from a Real Life incident he heard about while talking with some military personnel.
At the site where one of the Autobots crashed, we see a nerdy guy screaming "This is a hundred times cooler than Armageddon!"
The scene where Captain Lennox and his team are pinned down, need to call the Pentagon over a phone and need a credit card to pay for the call is almost identical to a scene in the film Heartbreak Ridge.
Standard Police Motto: Parodied. Barricade's alt-mode is a police car mode with the phrase "To punish and enslave."
Staring Kid: Several, one notable one is the girl who has a transformer land in her pool.
Under The Truck: Captain Lennox grabs an abandoned motorcycle in the first film, drives it straight at the Decepticon walking away, and puts it in a slide right through his legs, while firing his assault rifle and Grenade Launcher straight into said Decepticon, killing it.