Oh man I've played through Mass Effect 1 seven times--4 times on the PC and 3 times on the X360--and I'll probably go back one day and play it an 8th time. The only other game I've replayed more is Half-Life 2, which is a game I revisit at least once a year to keep my grounded.
I love this game. The atmosphere, the voice acting, the story (it gets goddamn EPIC), the side missions, the codex (oh man don't skip reading these because the lore is really cool), the powers, the conversation wheel (you get XP for certain rare choices unlike ME2), the score (every time I fire it up the game and it sits on the menu screen with planet Earth and the music playing, I get so excited) and the exploration of everything is all amazing! Yes a lot of the planets with side-missions look the same and the Mako can be a pain to drive because it's squirrelly as hell, but man is rad to just go out and explore.
The combat and some of the other oddities, to me, really help the game stand out. Yes the combat is a little wonky at first, especially now that the game is a few years old, but it's fine once things get rolling and you level up. Give it a few hours, unlock some powers for Shepard and you'll be fine.
What class are you playing? My recommendation is always to go with a female renegade Vanguard, and if you're not into playing an hardass then go with a Paragon. But the female voice actress is AWESOME, and the Vanguard class is a devastator at higher levels!
God. I might have to play through this again during the holidays.