"Do you want...?" is really heavy! It's not polite, so please don't use it for offerings, unless you have a close relationship with the person you are talking to.

"Would you like to have a drink?"
"Would you like to have something to drink?"

And then, DON'T SAY "I want (this or that)", you BRUTES!
Be kind, be polite, say "I'd like..." and remember to pronounce the "d"!

Any questions? Your own examples?

[Modificado el 7-10-2005 de Profe de inglés EOI]