Absolutely eat at Stripsteak at one point, Michael Mina's steakhouse at Mandalay Bay. Best steakhouse on the planet as far as I'm aware. They serve as an app 3 different kinds of truffle fries, and you'll never believe that french fries can taste that good.
Depends on your budget really. Joel Robuchon might well be the best restaurant in the US, its at the MGM. Guy Savoy is up there as well at Ceasars. Some less expensive but memorable places would be a place called Twist, which will have some food you won't find anywhere else.
If you like clubs, check out the new one at MGM (Hakkasan sp?) just opened and is like 5 stories and 80,000 sqft of awesomeness.
For pool action, do Wet Republic at MGM as well. My personal favorite thing to do is check out the dueling piano bar at the center of NYNY, easily my favorite bar. Golf, I don't know if there are amazing mid-tier options, you'd probably end up at Angel Park. Can splurge and go for Shadow Creek, that's the best course out there.