Bicycles represent my most Mustachian and least-Mustachian passion. On the one hand, I've religiously bike commuted and saved thousands in gas and maintenance as a result. Yet I also enjoy making my road bike vaguely resemble the racing wonders of the Tour de France, even if my engine isn't anywhere near justifying it. Oh well, you gotta live a little right?
Tires: Gatorskins have never let me down when it comes to road commuting / training tires. I rode Schwalbe tires on a Pan-American ride, Alaska to Argentina, and I don't think they can be beat in the realm of surviving-the-zombie-apocalypse-or-fat-tired-adventure-of-your-life. Great MTB and touring tires.
Fenders: Had good luck with the Planet Bike Cascadia fenders on a Surly Troll. No complaints, easy installation, no rattling or issues.
Panniers: Got some old Arkel Samurais. Heavy, but built to last forever and totally waterproof. Have seen these for ridiculously cheap prices on eBay. Insane. Would buy them again in a heartbeat. Otherwise, I think Arkel / Ortlieb is all the gold standard. Panniers for me are only really a touring thing...commuting or errands never requires more than a backpack for me. If I was loading up groceries I would rather have a trailer. If I had a regular commute carrying clothes and computer etc. I can imagine that panniers and racks would be more practical.
Racks: If you care about weight, get Tubus. If you don't care about weight, Surly Nice Racks can't be beat. We beat the hell out of them, carried everything on them often in excess of the max weight capacity, on nasty backroads from Alaska to Argentina and they are still going strong.
Headlight: I have always wanted to try dynamo but never gotten the chance. I've never used better than Light & Motion when it comes to rechargeable. Only other brands tried would be Blackburn, Niterider, etc. L&M is a great company and their stuff is fantastic. Well designed, easy to use, and great visibility from the side which makes them a great buy from a safety standpoint.
Taillight: Used both of the Light & Motion taillights, both fantastic. Their upgraded one has an aero mount that fits on the back of my road bike. Very bright, sleek, easy to use.
I have a single speed rigid Surly Troll that I am considering converting into a part-time Dynamo hub commuter. For now it's basically an urban bike to run around for short rides or errands, lock up at the bar or the beach, or borrow to a buddy to play around on some single track. Fat tires, simple drivetrain and disc brakes, etc. A dynamo hub setup with some lights would add some versatility...
My dream is to have a fleet of bikes in the garage, ideally acquired used and well kept. Currently own the single speed Troll for errands / around town / lock up at the bar / abuse. I've also got a fancier mountain bike that's my do-it-all adventure, tour, ride for fun bike. Finally I have my road race bike that I commute with because I love riding it, and a 12 mile one way bicycle commute is more fun on a fast bike.
Surly makes great stuff. I really like belt drive and single speed drivetrains. Simplicity wins and climbing steep hills without extra gears builds character. If you ever get the chance, use an Alfine or Rohloff and you'll never want to use anything but an internally geared hub for commuting / touring / mountain bike for the rest of your life. I've got a belt-drive Rohloff MTB / bikepacking / touring bike and it's gnarly.