Both Assassin's Creed and R6 Vegas are poorly optimized and buggy console ports. I see that your standards for PC gaming are very low. Are you enjoying the fake anti-aliasing with Vegas2 that you get (the blurring)?
A short list of incredibly buggy games that I have come across: Rainbow 6 Three, Rainbow Six Lockdown, R6 Vegas 1, Ghost Recon Advanced Warrior 1, Ghost Recon Advanced Warrior 2, Silent Hunter 3, Silent Hunter 4, all of the later Splinter Cell games, IL-2 Sturmovik (as much as I loved that game it was buggy and had a really awkward interface).
I have since stopped buying UBI games. Too many are left buggy and abandoned.