@CA: Probably hacking (if you're going for a stealth playthrough).
If you max your hacking by the time you get into Tai Yong Medical, the level will go a lot smoother. Plus, you can get more exp, and more Praxis, by hacking.
Get your storage and movement abilities quick as well. As well as wall-punching. You can find a lot of upgrades, Praxis points and other stuff by wall-punching.