1) The smart and lazy---they'll find the easiest way to do the job (or automate it).
2) The dumb and hardworking---you an tell them what to do and they'll do it exactly how you tell them to.
3) The dumb and lazy---they won't help, but they won't necessarily hurt either (just the bottom line).
4) The smart and the hardworking---terrible combination.
I actually have experience with the fourth type of person. Twenty years ago I was doing some consulting work for a bank and had to convert a printed training manual into HTML (mid 90s). The person helping me was very smart and hardworking. I'm smart, but a bit lazy. I had to argue with the person not to dive into one process (linking each word in the text to an entry on the glossary page) because it would take hours to do by hand (around 100 files, perhaps 100 vocabulary words). We actually argued longer than I took for me to code up the solution (using lex---we were working on a Unix system).