The nightlife is quite crazy. If you're up for it, you can party ‘til the sun comes up.
The beaches and the Sea of Cortez are quite nice, although the water was a little cooler than expected. Parasailing was one of the highlights.
As far as dining, it's hit and miss as far as quality and price. Talk to other vacationers to get recommendations while you're there.
The worst thing about Cabo is the constant badgering by the local vendors, hawking everything from Chicklets gum to T-shirts to jewelry. If you see something you are interested in, don't pay them what they ask. We were able to dicker with most to get things for a quarter of what they originally asked.
Quick Tips:
Don't take too much money with you when walking around town. When you DO decide to bargain with the vendors, make sure to only have the amount you are willing to pay in your pocket. Don't pull the money out of your wallet (you'll get a much better deal). Another MAJOR suggestion: WATCH THE DRIVERS!!! I wouldn't recommend renting a car: all of the drivers are crazy and don't abide by any traffic laws.
Best Way To Get Around:
Unfortunately, the best way to get around is by taxi. There's a ton of them around, but they are quite expensive. Make sure to negotiate the price BEFORE you get in the cab because you can get worked over if you wait until you reach your destination. Walking is a good way as long as your resort is near downtown, although walking at night is more than a little scary.