A bike for city commute - disc brakes, bar-end shifters, tires

For a city commuter bike, don't bother with disk brakes - go for simple rim brakes. You'll want the reliability over all else. You don't need disks for most types of road cycling, as the limiting factor for grip is likely to be your tyre anyway.

As regards shifters, go with whatever is comfortable for you. I like the combination of brakes and gear levers in the same unit, as you don't need to take your hands off the brakes to change gear. This is very useful in traffic.

I would also recommend touring tyres - offroad tyres lose too much power through rolling resistance, but you want tyres wide enough that you have some comfort and puncture resistance. You could also look into self sealing tyres.

Generally you should try the bike, and see if how it feels, including using the components feels good to you, if not look for something else.

If you will be riding no matter what the weather is, I would recommend looking for bike that has internal hub brakes, a full chain-case (which with gearing would normally require hub gears too), and full mud guards (fenders). With a setup like this, the weather will cause few problems to your bike and it requires a lot less cleaning and maintenance.

Normally a set up like this is found on the classic roadster/dutch style bikes, you will not normally get as fast on a bike like this, but if you take your time you are not going to get sweaty and wont need to change clothes at the end of your commute. Over 7 miles the slower ride will add very little time to your commute. The problem with a heavier bike like this could be the hills. There are lighter bike with more "sporty" geometry that are available, with the features I mentioned earlier.

The hard part may be finding a shop that sells this type of bike near you to try it and see if feels good for you.

Another thing to consider would be lighting, for the type of bike you mention, I am presuming you would use detachable lights which run on batteries for cycling when dark. For a simple day to day bike a hub driven dynamo which power both front and back lights is a good consideration.

You might find more general commuter bike buying, and bicycle commuting advise in these questions:

• What do you wish someone had told you before your first commute?
• Bicycle for 2 x 30mins commute

My general advise for your specific points would be:

• Rain IMHO means you want fenders, unless you enjoy turning up at work with mud (or worse) all over your face.
• Disc brakes usually mean more expensive bikes and slightly less maintenance. If you can afford them, and you can park your bike somewhere safe both at home and at work then go for it. Otherwise, V-brakes are almost as good wrt stopping power and durability.
• Maintenance wise you might consider an internally geared hub rather than a derailler. Any shifter that will at least allow you to keep your hands on the steering wheel will do.
• A little wider and some threading is enough in most commute situations.

If you mean Vancouver, BC, I live to the south of you between Tacoma and Seattle and commute 7 miles one-way up and down hills year-round. I use a steel touring bike with a front triple and wide gearing on the rear, though I really only use the granny for hills on longer touring rides. No bar-ends for me in commuting. I need to change gears too often and in traffic. I like drop bars with brifters where I have my hands in position to make any speed/gear adjustment without taking my hands off the bar or my eyes off the road. Bar-end shifters are cheaper and easier to repair/replace, so I guess that why some touring riders like them. I've got cartridge pad cantilevers, but would probably have bought discs if I could have found them on the right bike (fit and price). But... the cantilevers are a breeze to maintain. Wet weather commuting takes a toll on them, even if you have the time and place to clean the bike. With cartridge pads, replacing pads is usually a 10 minute job and requires no cable adjustment. Internal hub would be nice, but I wasn't willing to pay for wide enough gearing for the hills. So I replace chains 2-3 times a year and a cassette every other year. I ride 700x28 or 700x32 puncture-guard tires, but I'm looking at a Conti' 700x37 winter tire for the next cold, rainy season. I wouldn't commute on anything narrower than the 28's, unless all your roads are smooth. Fenders? Yes, full fenders to keep some of the crud off you and your bike.

My city commuter has Shimano drum brakes, and an internal hub, and I love it. The drum brakes are very low-maintenance and impervious to the weather. They're rare today, having largely been supplanted by disks, but if you find a bike with them, consider it.

Likewise the internal hub, but it is lower range than a derailleur would be, so depending on your hills, it may not be a great choice. In fact I got my bike from a neighbour whose commute took him straight up a hill; mine is in the opposite direction, largely flat.

And as others have said, fenders, and a rear rack for bags. You'll likely be carrying papers, a laptop, your lunch, maybe shoping; that weight doesn't have to be on your butt, and a backpack makes it hard to look over your shoulder to see what's behind you.