Money

Some of my thoughts:
1. Bring as much as you want to spend. This is different for everyone.
2. Bring USD or travlers checks change of pesos in the DR when you get here. The exchange rate will be better. DO NOT exchange at your AI resort even the airport usually gives a better rate. Until you get the hang of things do not use street changers.
3. Bring your visa, but you will get a different rate then paying cash and many places do not accept credit cards. Also let your visa bank know that you are traveling to the DR. The DR is "high" risk for credit card fraud and they will turn your card off after the first use if they are not notified. They actually turned ours off even after being notified. So if you are going to rely on credit cards bring two different ones.
4. Get off the AI resort and explor the local environs. Take only the amount of cash that you need that day with you. Carry a copy of the front page of your passport or a copy of your drivers lic with you. You may need these to change money.
5 ENJOY YOUR TRIP

Bob K

Instead of travelling with a large amount of dollars it might be smart to check out how much you bank charges for using an ATM machine in the DR. You can get pesos from an ATM machine mostly at a very good exchange rate, and whereas the opportunities to pay with dollars or credit card are limited, you can pay everywhere with pesos. But all depends on how much you will be doing outside the resort.

Just bring US$ and convert at a cambio when peso's are needed. Most business establishments in tourist area's accept the $US.
Leave your credit card in your wallet, there is too much credit card fraud for my liking.

I would agree with ggrande, but check the usage fees and cost of the aTM's before you go.

Pay in peso's to avoid paying the higher tourist prices.

I took US$ and changed it when i needed it, you should have a safe in your room leave it in there and just take out the amount you need for the day. As for how much to take, it depends whether you want to do excursions how many people you want to but prezzies for etc. Its pretty cheap to eat and drink outside the resort and you'll miss out on alot if you stay "in jail" all the time!
Also dont think you have to book excursions from the tour reps you'll get a better deal from local companies.

Nic

I always feel a little queasy about transporting my entire vacation pocket money budget in cash. If you are familiar with PayPal, consider getting their debit card. You can easily transfer just the amount of money you want for your trip from your regular bank account to your PayPal account online. (PayPal pays very good interest on balances - currently about 5%). This has the advantage of protecting your main account even in the unlikely event that someone puts a gun to your head at an ATM machine and demands your card and PIN. PayPal works at all ATM's, only charges a flat $1.00 per ATM withdrawal, and gives a decent exchange rate.