I'm in a similar situation, but I have the 15" model (Late 2008) and wish it was a 17" oneCurrently got a 2010 17" MBP but wish I had 15". Miss my 2009 15" MBP I had before it. Only sold the 2009 one because the battery had started giving replacement warnings. Once sold it found a brand new 2010 17" MBP going really cheap on eBay but just recently started regreting not just getting the 15" again as the 17" is just too big.
I was a little like that when I had my 2009 one every time I was in any Apple store I used to look at the 17" and think wow one day. Finally got it earlier than expected but after lugging it around for a year at university it's gotten too much and is time to go back to the more portable 15" again.I'm in a similar situation, but I have the 15" model (Late 2008) and wish it was a 17" one