Equipment
I was asked to detail my biking equipment, so I will. I'm not as much of a gearhead as I used to be though, so this is going to be pretty vague.

First of all, a sad note. That bike in my user icon was the best one I've ever owned, and I took the trouble to cart it back from New Zealand to the UK, but it was stolen before I could bring it out to America. It was a bit of a mongrel, as I bought it second-hand from a shop that had replaced many parts on it over a few years of using it for races, but it was a Cannondale frame, and what impressed me most was its reliability, so it left me with a lasting good impression of Cannondale's kit.

As for what I ride now, well I run two bikes, one of which I'm much more impressed with than the other.

The good one is a Giant OCR road bike. It's a road bike, so weighs very little, has drop handlebars and skinny tyres, and is a little more maintenance-intensive than most things you'd want to commute on. Unlike most road bikes it has 3 front chain rings (they often only have 2 to save weight) and a full range of gears, which I find myself using in Seattle. It has very small LED lights on it and no rack, because I really only use this one for fun rides by day (see previous comment about commuting bikes). It also has a fairly hard riding feel, so I tend to avoid poor quality roads. The upshot of all this is that I can go very, very fast on this bike. When I used to commute on this or a mountain bike, there was about a 20% difference in commute time, even though traffic and lights slowed me down a lot.

The less good one is my commuting bike, and I ride this more often. It's not that there's anything wrong with it now, but I'm unimpressed with it because since purchase it's needed significantly more maintenance than it should have done, and as a result it now has quite a few non-original parts on it. It's a Specialized hybrid bike (big wheels like a road bike but wider, frame shape and weight in between road and mountain bikes, straight handlebars because drops make me nervous in traffic), only it now has a third part rear wheel, as well as various smaller parts. The number of parts I've replaced in a little over 2 years of riding this bike has left me feeling disinclined to buy from Specialized again; I should get myself another Cannondale when it's time to replace this machine.

As for accessories, this is the one I use to carry stuff, to ride at night and to ride in the rain, so it has a lot more stuff on it. There's a rear rack, of nondescript manufacture (I've never encountered a bad rear rack, probably because it's such a simple part), and to which I attach Ortlieb roll packs, which I strongly recommend because they're the only bags I've ever used that do a really good job of keeping water out. There's a computer, the brand of which I can't remember, but which I mainly use as a clock to remind myself how late I am. There are multiple reflectors both in the wheels and at the front and rear, because they're light and cheap and it makes a big difference to visibility. And the most important things are the lights: I have two sets of horizontal-bar rear lights, because the bigger an area of a driver's retina you stimulate, and especially the wider a horizontal range, the quicker that driver will respond to your presence. I use both on steady, because I believe this is better for safety than blinking lights that draw a driver's eye too effectively, distracting them from the road and causing them to drift across. In front I have two lights, one of which is a Cat-Eye (another brand I've been happy with) multiple-LED type and casts a moderately powerful beam (enough for Seattle night riding; wouldn't have been enough in Cleveland where the streets are less well lit), and the other is a baby 1-LED thing that goes on the other side of the handlebars to give that horizontally-extended area of light.

Also, both of my bikes have toe clips. It might be time for me to upgrade the road bike to proper clipless pedals, but certainly for the commuting bike I find toe clips to be a good compromise. They give me a lot more power (especially from a standing start - I can do 0-10 as fast as most cars, and while that may sound silly it is actually important for safety because it makes drivers less desperate to squeeze past me), without requiring that I wear special shoes.

And then there's the matter of clothes. For general advice, REI is a good resource, though they do tend to over-emphasise the importance of having specialised everything, down to the socks. I'm about to list a lot of gear; I don't think it's necessary to get these all before starting to ride. A suggested order would be: helmet -> gloves -> shorts ->

I almost never ride the road bike in ordinary clothes, because it has a hard seat and a hard ride. The seat is great, provided I wear padded shorts, so I always do so. I commute in ordinary trousers, though never the white pair I own (impossible not to get them stained), and preferably jeans because flimsier trousers get a hole worn in a suspicious crotchish location by the seat. To wear trousers on a bike, trouser clips are essential; these simply stop the clothing from getting caught up in the chain and gears. I agree with dagoski about the unimportance of upper body wear, except in the rain, so I generally wear yesterday's shirt, intending to get changed as soon as I'm done. Because I don't have special cycling shoes, I tend to wear old, stiff-soled pairs. Old because toe clips are really bad for shoes that you want to keep looking nice. Stiff-soled because that increases pedalling efficiency and prevents foot cramps (and proper bike shoes are stiffer-soled than anything intended for walking in). I never get on the bike without a helmet, and rarely without gloves. The gloves aren't a safety issue, but they make a big difference to comfort. Then there are glasses. Sunglasses are obvious, but it's also useful to have some yellow lenses (increased contrast at dusk and in grey weather) and clear ones to keep the wind out of my eyes when it's dark, but this can end up being very silly, so I got myself a pair of glasses with interchangeable lenses.

And finally, rain. There is no way to cycle while completely insulated from the effects of rain, so my preferred solution is to have a change of clothes for when I get to my destination. Because this isn't always possible, I do have some waterproofs. dagoski is right that waterproofs cause sweating, so they are less than ideal, but fancy ones cause somewhat less sweating, and there are days when this makes the difference between me biking or not biking. I recently shelled out for a better jacket than I used to use, and it makes me very conspicuous (they're not joking about the "shock yellow") while also leaving me a lot drier than its predecessor did. I also have some waterproof trousers, though they are of lower quality and it's about time I replaced them.