There's no single place that defines Stormbreaker as much as Sayle Enterprises. This evil lair is where most of the novel's action takes place, and its unique characteristics emphasize the terrifying predicament that Alex finds himself in. However, we can gain a lot more insight into the novel by comparing this den of evil to the headquarters of the "good guys" (to explore why we put that in scare quotes, read up on Mr. Blunt in the "Characters" section)—the Royal and General building and the London Science Museum.
Dr. Evil's Lair
Herod Sayle sure has studied his predecessors because his evil lair wouldn't be out of place in Austin Powers. To start, the whole building is surrounded by a "twenty foot high" fence "topped with razor wire (7.14). Intimidating, right? He even has a creepy office, complete with a freakishly large killer jellyfish—it's not quite a shark with a laser beam on its head, but it'll have to do.
While the facade of Sayle Enterprises goes for an antique, creepy vibe, its depths are much more high-tech. Alex notes that he "could have stepped into the next century" (8.13) when he finally reaches the transition between the two. Interestingly, Alex also makes this observation at the London Science Museum, illustrating how the growth of technology is affecting everyone.
See, in Stormbreaker, the good guys really aren't that good. The Royal and General building (a front for MI6) is hardly a more inviting or friendly place than Sayle Enterprises: In fact, Alex compares its lobby to that of "a cruise liner" (3.21). Like Sayle Enterprises, there are plenty of secrets hidden in its depths, but MI6 is simply better at hiding them.
The London Science Museum is the setting for the novel's climax, and fittingly so. Like the two locations previously discussed, the London Science Museum is stuck between the past and the present. But that's not the only reason why it's the perfect spot for a climactic scene—the novel is quintessentially British, reflecting the nature of the country that Alex is growing up in. By the end of the novel, however, it becomes the country that he saves.