[STEAM] Mass Effect is $10 USD on Steam (for this weekend)
Seems like one of the better weekend deals in recent memory, especially since I've never played it!
Edit: It looks like there's no Securom on the Steam version too (for all EA games), so no DRM double whammy.
Edit 2: It looks like you can get the Bring Down the Sky DLC for free. However, if you want Pinnacle Station, you're going to have to buy it through EA's crappy store/download manager and maybe deal with some awkwardness. Something to consider if you're interested in the DLC.