That being said, clothing made specifically for the bike does have it's place, and does offer benefits that you don't find in "normal" clothes.
And, if your bike specific clothing is able to make the transition to "normal" everyday wear? Well, that is something special.
Last Fall, Chrome - the makers of fine messenger bags and whatnot sent me one of their Cobra merino hoodies. I don't think I've taken it off since then.
It is simply one of the softest, most comfortable items of clothing that I own. It's lightweight and thin, but at the same time warm. It has an understated, casual, off the bike style yet still offers several features that you appreciate when on the bike.
First off, the cut of the hoodie is very trim. The merino is naturally moisture-wicking and temperature-regulating, as well as being odor resistant. It also has longer sleves and torso so it doesn't ride up when you are over the bars. The longer sleves also have a thumb hole - my mom saw that and offered to repair the "tear" in my hoodie one day - which is nice when the weather is brisk. The hood is deep and the colar is tall to protect you from the elements.
My favorite features are the pockets. Along with the front pockets - which are fully zippered - the Cobra hoodie has a full pass-thru rear pocket for storing gear, and a key/stash pocket on the right wrist.
All of this greatness comes with a price. In this case, that price is $160 ($100 if you forgo the merino and get the standard Cobra hoodie).
More info can be found here.