Which are the best Twitterers for a newbie to follow?

It really depends on what you like to read, I'd say. As far as people go, I find these ones both personal and quite entertaining:

http://twitter.com/hotdogsladies
http://twitter.com/candice

These ones are a little more serious but insightful, also very good:

http://twitter.com/maureen
http://twitter.com/timoni

If you like the funny parody types of accounts and you're a starwars fan, this one is always a hit:

http://twitter.com/darthvader

and finally, for interactive profiles, I find these to be really fun:

http://twitter.com/strawpoll
* lets you vote on a simple daily question

http://twitter.com/rtm
*lets you use twitter as list making tool