Bike upgrade: hydraulic disc brakes
... from cables (known as mechanical).
My Giant Escape Disc is now equipped with Teppan Yaki SP5 floating stainless steel rotors and Shimano Deore M596 hydraulic brakes (opposed 2-piston design) with sintered pads. These brakes are 'bottom end' MTB (this bike is actually a hybrid) but according to Singletrack Magazine have "gained some of the features only seen on the top-end group (Servo-Wave braking) and feature an excellent modulation and easy maintenance due to Shimano's one way bleeding system."
Incidentally, I see the 2011 Escape disc, which mine is, is described as having a carbon composite fork. I'm sure it was steel when I bought it last year. Anyway that doesn't matter as I had a suspension fork from the start. It also came with cable disc brakes which I found surprisingly useless (although better than cantis). The cable brakes were spongy and noisy and frequently required new pads at a cost of around £30 per set front and back. The hydraulic system is superb in comparison to the cables. I tend to cycle in hilly terrain and the brakes matter.
Mountain bikers know all about disc brakes now of course. When I went mountain biking in the 1990s hydraulics were not as common as they are now – mine had V-brakes: quite effective but they wear out your rims. Unless you are cycling on clean roads in fairly flat country, discs seem to make much more sense. I also like how you barely need to squeeze the lever. I will never buy another bike that does not have hydraulic disc brakes.
One of my local bike shops doesn't sell MTBs because he doesn't fancy messing with hydraulics. He is an experienced mechanic and builds excellent wheels but it seems to me he's behind the times. The LBS where I got these new brakes reckon they are easy to bleed. I'll see if they're right in a couple of years – hopefully not before then. The Teppan Yaki stainless steel rotors are more upmarket than the brakes. They are pretty light, and pretty. My hybrid bike is also becoming lighter and prettier. I'll be building new wheels for it next, but not quite yet.