I always go for rifle skill. At master level, the sniper rifle is automatically 100% accurate. No focusing required. A head shot will also kill any standard enemy, but be sure to aim for the neck or they will die screaming. Aside from that, it's pretty vital to make sure that you always have at least level two computer skill, which allows you to hack anything. The only thing that Experienced lets you do with computers is control security systems and, as far as I can tell, master level doesn't really add anything. It's also a wise idea to keep a GEP gun handy, as it will kill anything that the sniper rifle won't, even without any heavy weapons training. Sure it take eight inventory spots, but you'll be glad you have it next time you have a security bot bearing down on you.
Don't pick swimming because it's fairly useless...