i use a card i got from my bank, its a debit/credit card (visa). when i make transactions i always run it as credit, although i don't think my bank is charging me interest or any payments of any sort (if they are its an incredibly small amount since i never notice any unaccounted changes to my account balance).

i don't really need a good credit score since i never purchase large value objects via payment plans, i save my money and then pay the full value in cash so to avoid ridiculous interest rates, but it would be great to know... without paying some credit firm to compile a credit report for me.

(In the US) Last I knew, no. That is, having the card and using it is as "credit" is not reflected in your credit report as a listing they keep track of.
Debit cards with Visa/MC logos do not equal them being actual credit cards because you are not "borrowing" money, even when you use the credit option. However, if you use the "credit" option, what it does (my understanding) is it can take a few days before being reflected on/to your bank account ... whereas "debit" is immediate removal. (edit: eg, it's kinda like writing a check)

Basically, if you are using an "online" method of using the debit card (have to slide it thru the reader/put in your PIN), there's not really any reason that I'm aware of to use it as a "credit" - eg don't push that button on the pad, just stick to the debit option. For one thing, many cards may have a dollar limit of how much you can use the "credit" option for as a method of reducing overdrawn-issues from the delay (vs. only being limited to total funds in your account via debit/online-PoS method).

If you're in a place that will take the debit card but does not have a reader/machine that accepts/deals with the PIN, then you may want to use the credit option (signature) instead.
Obviously, if you use the credit option and then have not enough funds in your bank account when the "charge" is posted to your account, that would likely be considered check-fraud or something, and could thus be reflected on your credit score (edit: if not resolved etc). But the use of it alone will not show up.

Lastly, using a debit card can apparently encourage some places (like rental car companies) to run a credit check, because they're a little more paranoid about them vs. true credit cards, which can affect your credit score if it happens too often in a short period of time.

I don't know how it works in the US, but here, if you've never had a credit card, you will actually have a bad credit rating!

The point is whether you are "good for it" - whether you can be trusted with a loan amount. If you use a credit card, borrow money, and pay it back quickly, this should be OK - best, in fact. If you're in any doubt, pay most of the total back each month and just have a tiny rolling balance - as in, spend $100 and pay back $95. Just don't let the total outstanding balance keep rising - by the time they've slapped on interest charges, the leftover amount can mount up very quickly. Personally, I pay back the exact amount it says on the bill each month - that way if I get charged ￡5 in interest, then that's the "debt" I'm rolling over, which keeps the banks happy - but, crucially, I can afford to pay it back at a second's notice.

If you've never borrowed any money at all, then you wouldn't be considered trustworthy for a car loan or a mortgage because you have never proved that you can be trusted to borrow money and pay it back on time.

As far as I'm concerned if you don't have the money to buy a house or a car you don't buy a house or a car.

Eh, it depends on your ability to pay. If you know you can pay it back eventually, it's good to be able to acquire something before paying for it in full.

I took a loan at the start of this summer for my car. I should be able to pay it in 3 years. It's helped me out a lot socially (the car I mean).

I agree---if you don't have money to pay for something or make enough to pay back a loan in a far amount of time----don't buy it or charge it.

So what you're saying is that you'll never own a home.

Hey now, who's to say Steampunk doesn't have a spare 70k+ knocking about? Or rich parents...

Using a debit/credit card will add to your credit rating... as long as you remember to pay your bills on time and remember to use the credit side. The only difference between the two is that you can either draw from your checking account or you can use credit. It is like putting more of your eggs in one basket.