Agreed. For coming into DC, DCA is hands down the best option and by far the closest and most convenient (whether private or public transportation). The advantage to IAD is that there are non-stops from SFO/OAK/SJC. I don't believe there are any SFO-DCA non-stops, so you'll have to connect. But if you factor in the time it takes to get from IAD->DC, the connecting journey to get to DCA is maybe only an hour longer than the transcon non-stop.

If you choose a suburban hotel location, Bethesda is much closer to the Zoo than the Northern Virginia suburbs of Alexandria/Crystal City/Arlington are. From downtown DC, Bethesda and the NoVA suburbs are equidistant.

BTW, do you already have tickets to see Tai Shan?

http://www.usatoday.com/travel/desti...5-pandas_x.htm