Microsoft's minimal recommended use isn't really that deceptive, many people were successfully using this Speech Recognition Engine as far back as 1999 when the average user's comp only had 64 MB of ram and a 300 MHz processor. It's not technically Microsoft's Speech Recognition Engine on it's own that's the resource hog, it has more to do with what other programs the user is choosing to use in conjunction with it. Hal and especially Haptek are very resource intense programs on their own and then you add in TTS and Speech Recognition Engines, that's a lot of stuff running all at once and each requiring system resources. Microsoft isn't going to endorse, recognize or post any recommended usage requirements when using their products with third party programs such Hal, CyberBuddy or Haptek, that's solely the responsibility of the third party developers and authors, as well as the users themselves to try and determine.
Just as a general point of interest, the Microsoft TTS Voices and Speech Recognition Engines weren't technically developed by Microsoft themselves. They were acquired through a partnership deal where Microsoft purchased an interest in Lernout & Hauspie back in 1998 at which time their Speech Recognition Engine was considered the most accurate available. Two years later Lernout & Hauspie acquired Dragon to combine their technologies. The present free MS Speech Recognition Engine that's available has fallen well behind anything that's being sold by Dragon/L&H or ViaVoice today, but it's still a decent entry level speech recognition engine for the curious and those who want to explore the possibilities. The new Windows Vista will have a whole new speech recognition engine built into the operating system that will allow for even more voice interaction, including dictating documents and e-mail messages in applications and filling out forms on the web using voice commands, as well as manage Windows Vista and applications by voice. How good it will actually perform is yet to be determined but some of the reports by Beta testers have been pretty positive. Microsoft Agent in Vista will also support SAPI 5 Text-to-Speech and Speech Recognition components. Although this is exciting news and sounds promising and it's about damn time Microsoft upgraded these technologies, there's still a few other issues about Vista that concerns me, mainly with security and the whole admin user thing. I'll personally wait until it's been out for a while to make sure it's not another Windows Me flub and see if there's going to land up being a Vista SE version like with Windows 98.
I agree with barfy that spyware and trojans are a real concern for the average user and people need to be made aware and should educate themselves more about potential threats and problems. One of the problems that people should also be aware of is that the vast majority of anti-spyware (and even some anti-virus) programs are well known for creating "False Positives". Many free versions do this on purpose to get users to buy the paid version and in other cases False Positives are just an oversight or caused by the program seeing some code that is just doesn't like. There are only a very small handful of anti-spyware programs that are reasonably accurate and reliable. I personally never totally rely on the findings of any anti-spyware programs, if I suspect a problem or something triggers I do a thorough search and investigation about it on the Internet first to make sure it's actually a threat, and if it is I usually figure out how to manually remove it myself. Investigating and manually removing spyware, trojans or viruses can be a daunting task even for those with advanced technical knowledge so the average user is reliant on ant-spyware and anti-viruses programs to detect and try and remove the infection. A good rule of thumb is not to panic and potentially compound the problem by removing or crippling perfectly good software or system components, do a search on the Internet, there's lots of good help forums on the subject, even try contacting the software company. Also try and use more than one reputable ant-spyware program to double check that it's not a false positive, and even then still investigate it further. The main key is in prevention and taking reasonable precautions to reduce the risks of being infected in the first place, don't get too comfortable relying on a magic pill (software) to cure the infection, sometimes that pill can cause side effects and compound the problem.
Here's a resource that's a good place to start for learning about the various anti-spyware programs that are available
http://spywarewarrior.com/rogue_anti-spyware.htm