Could a tablet pc replace a notebook/netbook?

My current laptop has (most probably) died, and now I am looking for replacement.
My initial thought was to go for a netbook, I only want to be able to go on Internet, watch some Youtube videos and send/receive mail, no games or heavy stuff.
But of course there are now the tablet pc’s too and they seem to me to be capable of the things that I wrote above.
Can anyone advice me on this?
Is the operating system (Windows vs Android) important in the decision?