In the web-published novel series Shadow of the Templar, team leader Simon is a complete addict, to the point where he took to kissing someone who'd just taken a sip of coffee when, post-surgery, he was banned from the drink, leading to lines like "Oh God, you taste like coffee". The coffee maker in the team's headquarters is named "Mrs. Simon Drake (<3)".
Deliberately subverted in this podcast where the hosts open every show with "Morning Coffee". To date they have never once had coffee during this segment, with beverages sometimes deeply oddball to avoid it. Also some of the co-hosts do a segment dubbed "Evening Pint" where they drink nothing but coffee.
In the devisor labs at Whateley Academy, the mad scientists gather every morning over a specially designed brewer to enjoy coffee so strong it's... well, just read the quote.
"Imagine a twenty-gallon stainless-steel vat of water, heated by a kind of micro-fusion reactor and made to work as a giant engine of percolation. Add to this the whole deal a filter that literally rips every useful bit of anti-nutrient and caffeine in the grounds and you have yourself some potent stuff. Our coffee is considered a deadly weapon in three states."
Jericho, one of said devisers, is so addicted to coffee that he has a coffee mug holder. On his power armor.
The devisers have a regular coffee chant that's a blatant Shout-Out to the Mentats of Dune.
Murphy uses coffee to keep her ADHD under control. It works to a certain extent, but she usually ends up getting her coffee taken away because she's so high on caffeine that she's a jittery, giggling mess.
In "The Kickassian War" (an extra on the Kickassia DVD), The Nostalgia Chick becomes animalistic when she's deprived of coffee for a couple of days.
Used in this Lolcats page. A good example that having no coffee can be terrible for some people.
Dr Kondraki of the SCP Foundation is known to go on mass-shootings if he doesn't get his daily coffee fix.
Survival Tips for S.H.I.E.L.D. Recruits implies that SHIELD as a whole qualifies for this trope, as it has over a dozen rules associated with coffee. Starting with the Rule #1: Always make more coffee if you empty the pot. You do not want to know what will happen to you if you fail to do so.
Quite a few of the sporkers at Das Sporking use coffee as a means of staving off boredom or anger at whatever they're working on. Mervin has gone on record a few times as saying she's literally addicted to caffeine, getting intense headaches if she goes without it (although in her case, she drinks soda).
Warren: Grace! Gracie P! Are you having any fun? Grace: (on edge) Yes, Warren, thank you. [...] Actually, Warren, I really don't think this is... Warren: You know what, Gracie? I don't think you are enjoying yourself properly. What are you drinking? (takes her cup and sniffs it) This is COFFEE!