Should I wait for the event?
Come on, can't you really wait 4 days till 16th? If it was a month... But not even a week! hahah
If they say something about Air (I doubt they release it on 16th, but maybe relatively soon) good, then you decide what to do, otherwise after the event just buy the one you were going to buy
I'd say the same to those who always say "buy now": if it's not strictly necessary to have it for some urgent work, there's nothing wrong on waiting a bit if the next version is coming relatively soon (even more if there's an Apple event the next week, and the next version isn't supposed to be just a new CPU model). Not saying, thought, to be forever waiting for the "best new ultra redesign to rule them all", but right now I think it's worth the wait.
p.s: I've a MBP 13" 2010 which isn't the powerhorse right now, but still can do the work with it, so I'll wait to the Air redesign, even if it isn't released until Mid 2015.