Last time I posted a "So, what's new" entry was when we release 4.0 ~3 years ago (can't believe it's already been that long..). Now I get to talk about what's new in the 4.5 GC. Actually I just talked about this with Channel 9 and here's the link to the video: http://channel9.msdn.com/posts/Maoni-Stephens-CLR-45-Server-Background-GC 

Enjoy!