I don't stress too much about my main commuter's weight...it has racks, fenders, sprung Brooks and lighting...of course it isn't light. I didn't chose the lightest parts either. It can be a little annoying taking up and down stairs, but riding is smooth and it has nice easy gearing to compensate.

http://i936.photobucket.com/albums/a...lk67/photo.jpg

I use this with my wife for errands, fun and whatnot...the weight and bulk make it a pain to move, and it flexes a bit...but it rides nice and smooth with a sensible gear ratio.

http://i936.photobucket.com/albums/a...7/IMG_0657.jpg

i ride with water bottle, spare tube and tools. I keep clothes at work and change them on weekends or when not riding.

My summer commuter bike weighs 15 pounds with pedals. Full carbon road bike with a Record drivetrain & carbon tubular wheels. I have a 40 minute commute each way, with restrooms and water enroute. So I don't even have water bottle cages. I carry a spare tubular tire and a mini pump, essentials tool kit and a cell phone in a small backpack. In the last 10 years I have only had to use the cell phone once to hail a cab, when my spare tire proved to be faulty.

My winter bike is a steel-framed flat-bar custom with an Alfine hub, Vittoria Randonneur clincher tires and enough lights on the bar to cast shadows a block away. I'd guess it weighs close to 30 pounds. 700c wheels of course. Riding on either pavement or smooth gravel, there is no point in suspension that drains pedaling energy due to suspension bob, and also adds lots of useless weight. Riding suspension forks in the rain will also cause them to eventually fill up with water which will turn them into a corroded, seized mess.

Switching from the summer to winter bike is wretched misery. If you haven't ridden a 15 pound bike, you may not want to. It is is a life-altering experience that will spoil your tastes forever.

The shop is right.

I'm on the end of the spectrum not bothered about weight (flat commute), I would rather have what I need for repairs etc...
My commute bike is 50 to 65 lbs loaded, depending on whether I carry my laptop, and how much food I bring for lunch that day.
I use panniers, not a backpack, it's easier for me.
I did a 500 mile bike camping trip once at 90 lbs total (not including my body weight), yes it's slower, but really, so what?
On my commute, I'm looking to do more work, not less, so it's a good trade off for me.
For weekend fun, I also have a 22 lb road bike. Fun yes, but it's easier to break something or flat, so I've never used it for commuting.
To each their own...

23.4 lbs unladen

I have no plans to switch to the road bike for day to day commuting - the convenience of being able to carry everything I want and need, and the relative comfort of the commuter more than make up for the extra time. However, it is nice to know that I can shave significant time when necessary.

I hardly notice the weight of the backpack - perhaps because I used to carry well in excess of 35 on a moderately regular basis -- but it interferes with my rear view in my mirror, so I avoid it for that reason.