Best Scan Tool Software For A Laptop?

[vicious6]

I am looking into getting some software to use on my laptop for tuning the Regals. Catch is, I would like it to be compatible with OBD II car as well so I can troubleshoot them if need be. I guess what I am trying to say is one that will work with OBD I and II. Any suggestions would be appreciated!

Thanks,
Joey