Mass Effect Forum Rumblings

Both TeamXbox and NeoGAF have posts from people who've played Mass Effect at the launch party in Edmonton. Ex-1up editor chespace comments and even provides some screenshots, noting you can travel anywhere you see.
I'm literally scratching the surface of the game. So far, it's fairly linear but I've only had a few encounters on the first intro planet. Tutorial dialogue boxes are literally still popping up.

Still, I've been really impressed with the gameplay so far. There's none of the faux action game bullshit here a la Jade Empire. This is basically a 3rd person shooter first and RPG second, with a ton of other stuff going on underneath the action, as well as the ability to pause the action and tell your party how to kick ass.
SpaceGhost2K on TeamXbox notes the game is 6.74 GB in size and contains 2.5 million words.
To give you an idea of how huge this game is, Casey shared a story about the company they outsource to translate the dialog. They have a pay scale that they charge per word: 1-500 words costs this much, 500-1000 costs this much, 1000-5000, 5000-25,000 and 25,000 to 100,000. The guy asked how many words they were talking about. The answer? 2.5 million words. We laughed and imagined the guy on the other end of the phone, having visions of speed boats and Ferrari's dancing in his head.

The development team takes community input to heart and made a couple of significant changes to the way this game was designed that distinguish it from KOTOR or Jade Empire. In those games, you're given the line of dialog to choose and then the character speaks it, so it's actually redundant. In Mass Effect, you are given options based on the general direction you want the dialog to go, so that the actual spoken dialog is a surprise when you hear it.

They also changed the way the game saves are handled. There is an autosave setting as well as being able to do manual saves. But most importantly, you can go back and forth between characters of your creation and game save points. To illustrate, let's say you have a light side Jill Shepard and a dark side Jack Shepard. You play a point in the game as the light side character. You want to see how the same point would play out as a dark side character, all you do is change characters and replay the point. This is HUGE over only having the option to just replay the whole game again as (the other side.)
RPGCodex offers some screenshots of the lesbian alien lovescene, which strike me as somewhat stupid, if not outright juvenile.