The number one thing that jumped out at me during the conference was Google's report that there are 50x more searches originating from the iPhone than any other mobile handset.
Just to put that in perspective there are 4 million iPhones in the wild compared to 3 billion other mobile devices. This goes hand in hand with O2's report that 60% of U.K. iPhone users are sending or receiving more than 25 MB of data a month- which is unheard of on other handsets.
Android was only available on a few booths- AMD, Qualcomm, etc. From the demo I saw, it's clear that Android will offer iPhone-like touchscreen functionality along with a tightly bundled suite of Google Apps and browser. It's important to highlight that Android is using WebKit- the same as Safari on the iPhone (and Mac OS X desktop).
Opera was demoing their latest 9.5 release- showing off Opera Desktop, Opera Mini, Opera Mobile and Opera Wii. They've created a browser for many, many other non-handset devices (Wii, Airplanes, Archos, etc.) They allow users to sync their profile, bookmarks, widgets, etc across all devices. (This is the exact same functionality that Apple should be offering.)
I didn't see Mozilla, but Firefox is coming soon.
Great browsers, combined with device specific site optimization (e.g. iPhone) or server-side optimization (e.g. Novarra) mean 2008 could finally be the Year of the Browser on mobiles.