this is just from my med student perspective, but with the trend towards improving preventative and defensive healthcare, i would think derm, GI, and GU would be big as we get more aggressive with screening for skin, colorectcal, and prostate cancers respectively. i just did a month at our local VA and they got tons of each. seems like anyone with any complaint of GI bleeding got a scope and any rise in PSA bought a prostate biopsy (and i now know that a single prostate biopsy specimen takes a good while to review).
for the record, i think more screening tests are good for all involved - it's easier to treat an adenoma than an adenoCA, plus it's generally cheaper. good for pathologists (more screening colonoscopies), but also good for patient (less death from colorectal cancer).