I did a few side quests, nothing major. My character is now level 29 and is really starting to kick ass. I don’t know what the maximum level is, but I hope I don’t get there too soon. As for the main quest, I saved Liara, the daughter of Matriarch Belezia. She didn’t take the death of her mother too hard, and decided to join my crew.
Liara has another theory about the Protheans. According to her, the Protheans weren’t the first advanced civilization in the galaxy. It seems the rise and fall of major civilizations is a cyclic process. Every time a civilization gets advanced enough, something erases her from existence. The Reapers (the “something” that destroyed the Protheans) could be much more than just a machine race.
EDIT: I explored a few more planets, got a few more levels and advanced the story a bit. I repelled a Geth attack on a human colony and crashed one of their ships in the process. On the way back, I fought a giant plant that was mind controlling the colonists. Now I’m one step closer to Saren.