Depends... if it's my day off and I don't wish for my workplace
to call me in for extra shifts, then hell yeah, I can live without
my mobile! 
Or if someone's irritating me with sms or telemarketers are trying
to contact you, then yup! 
If I have a computer and good broadband connection, and a home
phone, and I'm staying home, then yeah, cause I can keep in touch
with my friends via other methods.
I have left the house without my cellphone a few times.
I've lived!
However, if you're on a date
or meeting a friend, then I wouldn't be able to live without my
mobile because you do need to confirm last minute details and
what-not.
Funny... growing up, we didn't have such nifty gadgets and yet, we
survived and people dated and got married too! 