Writing was on the wall...
I was wondering when this was going to happen, the writing's been on the wall for ages now, with Schmidt being booted off Apple's board, Jobs telling Google's 'No evil' mantra being BS, Google making a phone to compete with the iPhone, and what I believe seems to have been the straw that broke the camel's back: a software update enabling pinch-to-zoom multitouch on Android devices.
Apple is going after HTC as the largest handset maker as well as the maker of the Nexus One to set the precedent that Android (which is open source and thus not sue-able) is fine, except that it can't be used in it's current guise on a smartphone. Basically, Apple are saying 'Use Android for nettops, not smartphones'.
Succeeding here causes the precedent to build an insurmountable wall in front of Motorola (Droid) and Sony Ericsson (Satio etc) with their Android-based devices. Furthermore it may also cause Microsoft to tread carefully with Windows Phone 7 too, but since there's no Winmo7 phone on the market there's nothing there to sue against, as will Palm with WebOS (again too small a company to be of a threat to Apple).
While a lot of bickering is going on understandably about who invented what, what Apple did with the iPhone is invent/combine* (delete as appropriate) a variety of technologies and get them working together to create what we now know as the iPhone OS as a whole. Nokia famously said at the time of the iPhone's introduction 'We could do all the stuff the iPhone does on a phone, we just didn't think about it', and that's basically what Apple is trying to protect in both its suit against HTC and Nokia.
This is one of the issues with patents, that the whole ethos/usage model of an entire system like the iPhone OS can't be protected, only the specific cogs within it...
I can tell you right now, Android won't die as a result of this. What the best Apple can hope to achieve (and what they want I guess) is for Android to develop it's own UI and semantics that doesn't follow the iPhone OS as closely as it does... which IMO is entirely justifiable on Apple's part.
The suit also says something about using a DSP (in relation to a camera I think), which is probably the digital image filtering to clean up a photo image since the iPhone has such a terrible camera. This is in relation to Winmo6.5 devices, but Apple have been so behind on the mobile phone camera technology I believe this is just a smokescreen to portray the suit as not being out-and-out against Android, but a general one against HTC. Regardless, this part of it is IMO baseless and irrelevant.
PS: El Reg, can we have Google Demon/Angel icons as well as changing Bill Gates to Steve Ballmer? A Google demon image should be tagged to this post ;)