I first attempted to get Guild Wars running via Crossover 6.1 on my brand new Macbook Pro (2.4GHz Core 2 Duo, 2GB RAM, NVIDIA GeForce 8600M GT). I tried all sorts of combinations for this install. The best I was ever able to get was just past the login screen (which looked great and had sound). After logging in, Guild Wars would go to the loading screen for the zone. The progress bar would get to 100% and then the game would lock up. Every time.
Just out of curiosity, I decided to try to install Guild Wars via Crossover 6.1 on my older Macbook (1.83GHz Core Duo, 2GB RAM, Intel Graphics Media Accelerator 950). I actually got Guild Wars to run successfully on this machine. I created a bottle and installed DirectX 9.0c (from the Guild Wars Nightfall CD) and Guild Wars. Run the game with the recommended flags:
-dx8 -noshaders -windowed -dsound
It works! My theory as to these different experiences is that there is some problem with how Crossover 6.1 is dealing with the new NVIDIA graphics card in the new Macbook Pros. Hopefully this can be solved, because I would really prefer to use my superior machine.