$2500 is a lot of money to just walk away from. I'd probably have trouble with that.
I don't know what the population of shelter dogs is like in your area, either, but that might also be a factor to take into account. Around here it's uncommon to find nice Labs or Goldens in the shelter population (although it's usually fairly easy to find them in rescue, and in fact I might be picking up a Golden mix foster this weekend).
Fostering with the possibility of adoption might be a good intermediate step if you're really having trouble deciding.
ARCHMX TDCH Pongu the Insane, CD-C, RE, RL1X6, RL2X5, RL3X2 (GSD mix, b. Apr 2010)
Crookytail the Tigerwuff, RL1, ITD (Akita mix, b. Jan 2011)