Chris Sells recently went anti-GAC and gave his reasoning. Alan Shi answered this GAC phobia with a well-reasoned explanation.
Of course, if you think the GAC is advantageous for you, then you no longer need consider XCOPY or no-touch deployment strategies. You are going to need to create an msi to get your app to customers. Only you can weigh the good with the bad of the GAC. I will probably end up using an msi that contains a custom update facility.