Whatever DRM Win7 may have has been transparent to me.
I should qualify that statement with a bit of info - I am fairly tech-savvy (love to tinker, programmer by trade), refused to upgrade to XP SP3, had numerous experiences with Vista on other people's systems that made me avoid it like the plague it is on my own system and I have been running Win7 since the public beta became available. I love it. There's no question that Win7 is the future for me - I will only continue to use XP on older systems. I've read about the DRM nightmares supposedly built-in to Vista, and presumably continued in Win7, but I have yet to encounter troubles.
You may have read about Win7 removing the Stereo Mix (WAV) channel from the source channels for recording. I have also read that this is up to the drivers, rather than the OS, but I have been a bit disappointed to discover that the 64-bit drivers for both my HT Omega Striker sound card and my on-board audio are lacking this channel.
I haven't used Windows Media Player in probably over a decade (not regularly, anyways). I run MPC Home Cinema x64 and it works great.