When i took class at testmasters, poll showed 40% each for Water Resources and Transportation, and 10% each for Geotech and Structural. But i guess, people switched between geotech and transportation.
I will probably sit for the civil exam in a few years.
I'd probably do the Enviromental afternoon session.
I can do the water/ww treatment problems just fine. But the WR exam looks like it has more emphasis on open channel flow, hydology, etc. I suck at that.