Does it cost another fare to transfer from bus to bus, or subway to bus?

Also - do you agree that for a family of 5, for 3.5 days, it's better to buy a pass with, say, $30 on it and top it up as we go, rather than individual $4 per day passes?

Judi -
First of all, glad to hear you are travelling to my fine city.

Secondly, if you buy a "Metrocard" (they can be purchased at any subway station), there is no additional fare when you switch from bus to subway (or vice versa) within 2 hours. Subway to subway is no additional fare, as long as you are transferring trains at the same station. (You can't take the 4 train to 14th street and then walk across town to pick up another train. you must pay again)

You would need to take the train 3 times a day to get your money back on that $4 daily pass. I recommend getting one Metrocard and topping it off as you go. You can put any dollar amount on the card. Hope this helps, and enjoy your stay!

Go with the unlimited MetroCard for the days that you will be in NYC for the full day and sightseeing. May not be cost effective for the day you first arrive or the day you leave, but definately worthwhile for your "full days" in NYC if you plan on seeing the city.

If you're going to get on a bus or enter a subway 3 times in a day, the unlimited card is a money saver.

Although Chris gave you correct info about the pay-as-you-go metrocard, he neglected to tell you that the $4/person/day 'Fun pass' allows unlimited transfers between buses & subways - for that bonus alone I would disagree with Chris, and recommend ALL tourists get the $4 daily funpass. As stated, it only takes 3 rides a day - and that can be a ride as short as a bus ride for 10 blocks, because you're just too tired from all that walking - to have the Fun pass pay off - and beleive me, as tourists, I can guarentee you will take more than 3 rides /day on the bus and/or subway.
The funpass is truely the best bargain in NYC - beating The Stten Island Ferry and Grey Paypaya's hot dogs!

I agree with most of the posters here that it makes more sense to get the unlimited cards rather than pay as you go. If you have the unlimited, you won't ever hesitate to take that extra bus when you're a little tired (even if it's only for 8-10 blocks)or if there are delays in the line that make you get off at an earlier stop, or get off a bus when you see something interesting that you'd hadn't planned on stopping for, or even run back to your hotel or back to a store you've seen for a quick visit.
Also, with individual cards, you're more likely to split up into smaller groups when necessary.

And you'll never be stuck--if your regular Metrocard runs out and you want to use a bus, you'll either have to come up with enough exact change or run into a subway station to add to the card.

As much as anyone can guarantee these things, you won't be sorry if you DO have the unlimited cards,for at least a couple of the days, but you probabably WILL be sorry when you don't!

Two more details--if your group includes a young child (under around 6 or 7--but it is actually determined by height, not age), you don't pay subway or bus fare
at all. If you have a senior citizen in that group, he/she can get half price on individual fares but not on the one day unlimited $4 pass (you can get a half price weekly unlimited Metrocard, but you must apply in advance for a special photo ID card Metrocard, so it isn't practical for most tourists)

Before purchasing a card for $30 and adding money as needed I believe that only up to four people can go through the turnstile. There would be a delay of 20 minutes before the 5th person can enter the sysyem. Do check on this before purchasing the card.
If you plan your sightseeingdays by area there could be a day where you might use the system once or twice - pay as you go. If you know you are likely to use the system more than two fimes buy the $4 pass.

I imagine the $4 daily cards are the best: but: to make things both clearer and more complicated:

a regular Metrocard (not limited to one day) brings the cost of a ride down to $1.35, as you get a 10% bonus if you buy a card for $10 (or $15, I forget) at one time. (One regular full price fare =$1.50)

And: the regular card allows one free transfer in a two hour period.

So: depending on what you're doing: you can get up to six separate trips for $4.05 of your regular Metrocard money (3 x $1.35, on the principle of 2 trips for each $1.35).