I asked a similar question (similar, because people recommended a hybrid): What bike+equipment for a long daily urban commute?
The bike that I bought cost $700 after a discount for being last year's model, so it afforded/included disc brakes (and I like it very much).
The best thing about disc brakes is that they work:
- On a steep down-hill, and/or at top speed
- In the wet (riding in rain or snow)
- In traffic (riding on city streets at rush-hour)
For example, this comment:
Disc brakes stop when it's wet - I'm in Vancouver! Hydraulics have a lot more braking force - I can lock the wheel with a finger, with regular pads I had to squeeze hard and hope on the steep sections.
They're also useful, apparently, off-road in mud: if your rims get muddy.
If that's not the type, time, place, and speed of riding that you're doing, perhaps disc brakes are less important?
Now, I'm riding in the country-side instead of in traffic: so I don't need to do 'emergency stops'. Brakes are important, but perhaps more enjoyable are nice gears, and (especially) good tires.