I get labeled the "chopper guy" far too often.
The truth is that I ride a lot of bikes. Yeah, I got a snotload of choppers, and they are great for two-lane relaxed sightseeing. But I also commute my ass off, and I'm not doing it on a chopper most of the time. When I'm fighting Philly gridlock, I tend to gravitate towards sporty bikes. Past victims have included a Yamaha Radian, a Suzuki Katana, and my current mule is a Yam FZ6. I like using sport-derived bikes for commuting because I ride aggressively. They're fast, agile, and reliable. However, sport bikes aren't often built with "daily rider" status in mind.
As a result, there are five modifications I make to any sporty bike that gets pushed into commuting duty. All of them. I'm going to assume you're comfy(ish) on your bike, and it's running as well and fast as you need it to. That's another topic. These five items are quick and easy modifications intended to make living with the bike day-to-day easier. Best part? They cost about a hundred bucks total, for all of them.
You might not even know what a spool is. (I believe our British readers refer to them as "bobbins.") Spools are little doodads that thread into your swingarm to make it possible to use a rear stand (again, "paddock stand" to you Limeys), as shown in the photo up top.
A long time ago, most bikes had a center stand to allow users to remove the rear wheel, easily lubricate the chain, etc. Since they weigh a good bit, they have been all but eliminated on sporting machines. Spools are super affordable; probably 20 bucks or so. If you're a real cheapskate, you don't even need a rear stand. Just lift your bike up onto jack stands or wood blocks, as shown above right.
Upgraded headlight bulbs
Every bike I ride seems to needs help in the headlight department. Even the bikes with good lights can be improved. Bulb technology is crazy-good these days. In the past, I have had great success with PIAA headlight bulbs. I'm running a set of Sylvania Silverstars currently, and really like them. A word of caution: I steer riders away from the HID conversion kits. They're harder to install, illegal in many places, and don't work well because halogen and HID lights can't use the same reflectors inside the bulb housing. Better bulbs are cheap and easy to install.
Let's face it, when you're commuting, you're getting on and off the bike, you're moving around, and you might not always be in bike-specific gear. Sometimes you're wearing something more casual, and you may wind up with a belt buckle or zipper destroying the paint on your tank, or worse, denting it. A tank protector costs a lot less than repainting your tank.
Right-angle valve stems
If you have to stop at a filling station to top off a tire, it can be murder to try and get the big honkin' chuck on the end of the air hose past your big brake rotors. In fact, it's often flat-out impossible. Ninety-degree valve stems make it possible without a struggle.
SAE lead for the battery
A battery maintainer lead is great for keeping your scooter's battery in tip-top shape, and also for charging your phone or other small devices on the way to the office. Consider how deeply buried some batteries are. A lead for a maintainer makes using a battery maintainer easy, so you're more likely to do it. Just hook it up after you take off your gear. Many dealers install these before a bike leaves the showroom. If yours didn't, get one! This is arguably the most useful item on the list.
Look, blow the dough. Skip a few lunches, lay off the smokes for a couple of weeks, whatever it takes. I promise these modifications will make your commute better and easier.