Please keep your opinions about the technology to yourself. Most of the attendees are there to learn about the technologies. Your position as a speaker is to educate those people about the technology, not to use your position as a soapbox to voice your particular issues about a certain technology/company/etc.
I understand that you are entitled to your own opinion. However, unless I ask for it, I dont want to hear what your opinions are about Microsoft. I dont want to hear about what you think about Whidbey. I dont want to hear about how you think I should be accomplishing a certain task.
Also, when you're speaking at a conference, please make sure that you know your material before you start your presentation. If someone asks you a question, the answer "I don't know" is perfectly valid. Please do not try to bullshit your way through it. Believe me that most people will know when this is happening, and you will only succeed in making yourself look bad.
I've attended 3 sessions here at VSLive! where this has been the case. One of the sessions became so bad that I ended up walking out.