I have enjoyed playing around with the various social media sites on the internet recently, and I am going to try my best to use the sites I'm on better, and more frequently. I keep my FriendFeed widget on the sidebar with quick links to all of them, but if you want to follow or friend me on any of the main sites I use, here are the direct links:
Plurk - I use this a lot for just general chit-chat with friends, status updates, video and picture links, etc. It took a while to get used to the layout, but I really like the threaded format.
Twitter - I have been tweeting mostly blog updates, but I think I am going to start a pen log and more on Twitter.
Flickr - All of my review photos plus many more extra shots live here. I'm usually pretty quick to respond to any comments on my photostream.
A few others I use a bit are Delicious for general bookmark tagging for stuff I may want to circle back around to at some point, and Last.fm, which I scrobble to, but I'm not necessarily super active on the site itself.