Here's a nice collection of all the best 2.0 web software that are currently available on the net.
http://web2.wsj2.com/the_best_web_20_software_of_2005.htm
I was really happy to see one of my favourite sites del.icio.us noted as one of the best social bookmarking sites. I am going to try all the other cool sites (mainly voo2do and calendarhub) will present my thoughts on them as a blog entry soon.