As a big XM Radio and TiVo fan the announcement that has me most excited is this:
http://www.tivo.com/5.3.1.1.asp?article=194. I haven't seen any info on this since TiVo's original announcement, but my guess is that TiVo's recent move to make the Home Media Option features (previously available for an extra charge) avaiable to all subscribers is paving the way for TiVo/XM integration.
As far as getting XM into MC, I first tried using MC's own sound recording functionality which is fine, but there was no way to take advantage of one of XM's best features - showing the title and artist of each track. It was worth it to me to purchase
TotalRecorder for this purpose since it has the ability to parse the display in the XM PCR software to determine title and artist. To round things out, I am now using the free
ReplacePCR instead of the XM-provided software - it has scheduling features and keeps a complete relational database of everything played on XM. Very cool.