In re The Topps Company Shareholders Litigation, 2007 WL 1412990 (Del. Ch., May 9, 2007), read opinion here, is a decision of the Delaware Chancery Court that includes a comprehensive review of the policy basis for the "internal affairs doctrine". That doctrine provides for the law of the state of incorporation to govern the rights of shareholders and the duties of directors. This opinion balances that well-settled principle with the more pedestrian McWane [ 262 A.2d 281 (Del. 1970)] doctrine, which allows for a preference that first-filed actions proceed when there are pending suits in several jurisdictions involving similar parties and claims. The opinion is very detailed and contains extensive discussion of the factual and legal issues involved. It should be required reading for anyone who needs to be conversant about these issues.
The court explains, over many pages, its reasoning that the internal affairs doctrine is a more important basis to keep the case in Delaware, and to deny a motion to stay, as opposed to the principles underlying the "first-filed" McWane rule. In sum, even if other suits were filed first, a case filed in Delaware may be allowed to proceed despite earlier filed similar cases in other states if the issues are such that Delaware has a supervening interest in the interpretation and application of its own law, especially based on the policy reasons that buttress the internal affairs doctrine.
UPDATE: For more commentary on this key decision, see post here from the Harvard Corporate Governance Blog.
UPDATE II: Prof. Ribstein has scholary commentary on this decision, with reference to his prior writings on the topic, here.