It's up to you - all kinds of threads on this. I like splitting off /home, /usr/local (my stuff) and /tmp, /var (variable stuff) and leaving the rest on root. Such a root might be 2-4 gigs depending on how much you put on. Might want to leave a little more for breathing room. /var doesn't need to be very big - half gig is probably plenty, but this depends on what you put there - if you're spooling mail for hundreds of users it's different than if you've got ~/.mozilla for one. /tmp I actually like to make way bigger than it usually needs to be because a lot of apps dump stuff in there that can be huge and it's easier than pointing them elsewhere - gig, gig and a half that's almost always wasted but real useful when I need it. I take as much as I can for /home because that's the point of it all. But it's too variable to give a definite answer. You *can* just make a swap partition and stick everything else on one partition if you just don't want to bother with it.
As far as fs, I like reiser but ext3 is a good solid choice. Again, it's up to you.