I'm still not sold on Chrome. I started using it when I installed Ubuntu 10.04 ~1 month ago. It is faster and flash support is better (part of this may be due to the OS upgrade?), but there are several things I miss from Firefox. If I start typing things into the address bar it is not as accurate in suggesting pages (e.g. in Firefox if I typed 'f' it knew I wanted to go to
http://www.christianguitar.org/forums/, in Chrome it wants to take me to some other forum that I only visited a handfull of times). I can't drag tabs into my bookmarks to bookmark them. Adblocking seems inferior.
If you want to talk about something that "goes a long way towards making Linux usable on the Desktop", I think iPod Touch support in 10.04 is wonderfull. Not having to boot into Windows to manage my music is wonderful. I have long thought that a lack of iTunes/iPod support has been the biggest thing holding Linux back. Its not perfect now, but this change has gone leaps and bounds towards fixing this problem.