same here. i am a total backpack convert. i used to commute with a rack and trunk bag, but i just like the way a bike handles when it's as light as freaking possible and not encumbered with heavy racks and bags/panniers. i'm so stubborn about the backpack thing that even when i did an unsupported 900 mile LEJOG run all the way across great britain last summer, i did the entire tour with a backpack. the other guys on our tour thought i was nuts, but it's just the way i am.

Uhmm... the fixer (the attachment part) broke today morning as I was commuting in... going over speed bump... I know it was only loaded to 80% of supposed capacity. Time to see what Topeak says. Thankfully, the bag is hard foamshell which had some protection even when it was dropped at about 15mph and content inside were fine (including Galaxy S tab). Hoping it is isolated incident as another option for my road bike would be carradice SQR system and I don't like the look of it much.

Different strokes maybe, but I find my bike to be kind of slow and clumsy with a rack and panniers. I guess maybe I am too addicted to speed, but I find that when my center of gravity is up higher and more central (aka, when wearing a back-pack), I am much faster. Perhaps my problem is that I am a Cat 6 racer.

Have to agree with you on the Rack - Panniers set-up. I used a Topeak rack and MTX Trunk Bag with Panniers on my hybrid and thought it was the bees knees. Then following the rule of N+1, I picked up a Tricross Comp a few years back and was amazed at how light and quick a bike could be. I went with various types of backpacks, messenger bags to try and keep the bike light and sporty, but finally broke down and mounted the rack and Trunk Bag on the Tricross. Carrying a messenger bag was ok, but when I added the U-lock and cable, it was like throwing a brick into the bag.

My commute is totally flat, so the panniers really don't slow me down too much. You have to carry your stuff anyways, and for me, I'd rather have the bike do it than my back.

IMO,panniers go on touring bikes.. Sport bikes and racers don't look good with panniers..

I am a rack and pannier person as well. I like my bikes sleek but I also like to be able to carry what I need. I recently bought some Ortliebs and I love the incredibly simple way they attach and detach. I would never leave them on the bike for extended periods and the shoulder strap makes it easy to carry them. I have never noticed an appreciable difference in the way the bike handles with them.

orly?
Granted, this is a classic frame, but it classifies as a "sport" frame (club racer/randonneur)

I agree on modern Carbon fiber race bikes - a rack would look out of place.

Who cares about that?

Yeah, I guess I could have been more thorough with my response. It is not a purely aesthetic thing. Any race bike will have short chain stays, making heel strike an issue on just about any pannier. Also, most racing bikes will likely lack the necessary eyelets, so a rack would not only be awkward to install (P-clamps are a compromise at best).
Since the seatpost of such a bike would most likely also be CF, a seatpost-mounted rack would be a dumb idea, unless there would be a method of bracing the sides to prevent ANY rotation.
For a racing bike, a backpack is the best option IMO.

I've seen some CF commuter-oriented bikes, but that is a whole other discussion.

I'm personally a rack an pannier guy, through and through.

I did one ride with a backpack. Never again.

Backpacks can be hot, sweaty, and literally a pain in the back. Went from back pack to rack trunk and now to panniers, the latter change being prompted by the need to carry stuff for evening classes. I love not having the weight on my back and would never go back to a backpack unless my trunk and panniers all but the dust for some reason, and even then only until replacement could be procured.

Then again I now ride a Surly LHT with both front and rear racks so I've got plenty of places to mount panniers.if I were so inclined to ride a lightweight road bike to work I'd see the appeal of the backpack.