Upper Respiratory Tract
Largely this is covered by the ENT doctors. Hence, there's not actually a great deal in this bit. Laryngitis is important to know about, as are any other infections. The most serious is condition is upper respiratory tract cancer.
Lower Respiratory Tract
Again lower respiratory tract infection is a biggie and it can result in pneumonia or an empyema. In terms of more obstructive problems, the important ones are asthma and COPD - often referred to as bronchitis or emphysema.
Bronchiectasis and fibrosing alveolitis are two weird lung conditions that both cause clubbing, and finally, occupational lung disease doesn't really fit in anywhere else. I've decided to put it here. Good for me.
Pulmonary oedema is not strictly speaking vascular but is usually caused by some for form vascular problem. Sort of. Shut up. Anyway, pulmonary embolisms are vascular problems and medical emergencies. If you don't diagnose somebody with one they may die, making them dead and you a bad doctor. Pulmonary hypertension is also important to know about.
Lung cancer - not really a lot else to say. This page covers (or will cover, depending on when you read it) all the stuff you need to know about the various cancers affecting the lung.