1) Swype - It's just much less awkward to type with Swype because you don't have to shift the phone from its natural position -- holding it with one hand and interacting with it with the index finger of your other hand. Also, much easier to type one handed by Swyping with your right thumb, which is useful when you're, say, carrying something in your other hand. Plus, even over a year later, it's still fun to wave your finger around the screen and make words. YMMV.

2) In my opinion, the home screen shortcuts to individual contacts is way better than Siri. Tapping is faster than talking. Plus, I can see if they're online and IM them if they are. I even have one click video chat with Google Talk Video Chat natively supported. Here's a screenshot of what I mean http://twitpic.com/73xo6d

3) My Galaxy S2 can run for almost 40 hours on a charge with light usage, and probably around 24 hours of heavy usage, so battery life is not an issue as it was on the original Galaxy. I like being able to see my calendar at a glance or the weather forecast without talking to my phone, or toggle on a wifi hotspot in one tap. YMMV.

4) It seems minor, but makes using the browser a much better experience. Don't knock it till you've tried it.

5) Has nothing to do with Siri. It's a Chrome extension that works with your phone. I just click a button in my browser, and it sends a notification to my phone with a link to whatever page I have open. Really nifty for grabbing an address before heading out the door, and sending stuff to read later on the train.