Originally Posted by MichaelW
Modern roadbikes of any material are quite strong enough for regular commuting on the road.
The problem is the limitted tyre clearance and lack of threaded eyelets for mudguards and possibly a luggage rack.
Most road bikes use small-drop caliper brakes and can just about squeeze in a narrow 28mm. For practical winter riding you need a generous 28mm + about 5mm extra for fender clearance.
Some entry-level road bikes have the neccesssary threaded eyelets.
You dont have to fit bits to them but if you do want to avoid a skunk-like mud strip up your back you wont have to come crawling back asking how to bodge your frame using P-clips or clamps.
Modern wheels often have low spoke counts. Again they are quite strong and effective..until something goes wrong. They are not very maintainable and need special parts for repairs. A std wheel recipie such as Shimano 105/Mavic open pro rims is hard to beat.
Check out Audax/light-touring and training-grade road bikes. These often come with more useful long-drop calipers.
+1
The frames are usually plenty strong especially the steel ones but the tires and accessories are the weak point.
I believe the Surly Pacer is a traditional drop bar roadie with a strong steel frame, a little more clearance for tires and fenders and the necessary mounting points. This still uses caliper brakes and you can build it up how you like. It only comes as a frame so you'll have to get your LBS to build it up for you or do it yourself.
If you live in a dry climate or have a backup bike for poor weather you can use a road bike like the Trek 1000 for commuting when the weather is nice. It should be able to fit a 28mm tire for decent comfort and durability on the rough trails. I have two commuters myself, a fixed gear touring bike with fenders and rack for all weather and a track bike with 28mm tires squeezed in for when the weather is nice.
Craig