If you are one of the many who has bought into the recent rumor on the internet about Sony bringing back backward compatibility, it has been proved false. The Koalition has sent Sony an email, and this is what they had to say :
Thanks for your email
When we removed backwards compatibility from PS3, we said that it would not be coming back as our priority was to make great next generation games. I am not sure where you are getting your information from, but at no point did we say that there would be some sort of emulation being brought to PS3. At no point has this strategy changed and therefore I can tell you that there are no plans to bring back backwards compatibility to PS3. I think you will agree that the list of 1st party exclusive games for PS3 is growing quickly and the quality of them is great. Games such as LittleBigPlanet, Motorstorm Pacific Rift, Resistance 2, GT5: Prologue and the up-coming Killzone 2 show that we are very serious about bring exciting, innovative and fun games to PS3.
So, as you can see, BC is most likely, never coming back. You best option is to get a launch 60GB or an old 80GB.