That is true what Blaine said. The same goes for anything else too.
Getting the first model of anything is "usually" a bad idea. However quite a few times its worth getting the old model due to difference in parts.
A good example of this is alienware. The m17x R1 and R2 were aluminum. However the R3 is now made out of plastic and cheaper to make/manufacturer.
I don't have a mac yet, but I want to pick one up. Since they "might" release a refresh in a the next few months, and mostly at the same price as now, I will wait for a few months till one arrives. Hopefully rumors will come out early so I could find out if its worth the wait.
However based on this:
http://en.wikipedia.org/wiki/MacBook_Pro, we could see the new model come out next year, or later this year.
Macbook Pro release dates:
Late 2008 - October 14, 2008
Early 2009 - January 6, 2009
Mid 2009 - June 8, 2009
Mid 2010 - April 13, 2010
Early 2011 - February 24, 2011
Flip a coin...
Even based on the Buyers guide here:
https://buyersguide.macrumors.com//#MacBook_Pro
???
169 days
02/2011
317 days
04/2010
309 days
06/2009
237 days
10/2008
231 days
02/2008
266 days
It appears that the last 2 updates were about a year long (~300 days). So, yes, there can be a early update. However we don't know for certain...only Apple knows, or some worker who is making these products for us to enjoy.