Two cool card types have recently come out. The first is from
http://www.livecard.net/, they are calling it the "Battle Card", and it lets you compare yourself to anyone else on LIVE, to whatever end. Another cool thing is that if you register for their site you can create your own gamercard designs using a web-based editor.

The second is the "GameBar" card from
http://www.mygamercard.net/, which is an animated gif showing your overall gamerscore in the first frame, then the last 5 games you have played and your actual gamerscore % for each title. Each title is shown with its own title-specific background, it's a pretty cool card. Which is why I included it in my sig, until it was pointed out to me that animated images are not permitted, so I figured I would share it with everyone else. I guess you could use it in your msn space or myspace.

(This post contains an implentation of the LZW algorithm.)