I have a warlock on the Silvermoon server.  The first 18 levels were slow.  Then I met up with 2 good levelling buddies from the UK and the remaining 48 levels were quite rapid.  It took me from Jan 2006 to May 2006 to do the 60 levels.
I joined a raiding guild last month.  The best bet is to choose a guild that lets you choose how often you raid.  If you're compulsively addicted, then you raid every day.  With me, I tend to do Onxyia on Mondays (takes about 1hr 30 min), Zul'Garrab on Saturdays (takes about 3 hrs, before I got out clubbing) and sometimes, Molten Core on Fridays (4 hrs).
Still, I go clubbing 1-2 per month and the pub 1-2 per week.
I must say that WOW is addicted for me not because of the raiding but for the penfriends / acquaintances that I have managed to get.