Hey marcus, it depends on your community. One way to look at it is that sony has sold 140 million PS2 and 25 Million PS3. There are a lot more PS2 owners out there right now. However, when you're establishing a new collection, you want to look forward and not backward, and it's expected that the PS3 will have a good holiday buying season. But it really comes down to your community. Are they early adopters? Are HDTVs common? If so, PS3 is a good idea. If not, PS2 may be a better use of funds. There's also the fact that there are a lot of cheap PS2 games and almost no cheap PS3 games. The final thought is that last-gen technology is exactly what young people expect to find in a library; do you want to prove them right, or wrong? Good luck!
-eli