I'm currently performing my second Mass Effect playthrough (going for 100% completion this time before hitting ME2, as opposed to the first game where I suddenly ended up face-to-face with the end boss, killed him and hey presto, game over), which I'm admittedly playing on easy, but it was actually still somewhat of a struggle the first time, and there were plenty of times (especially when fighting Geth Armatures and Colossi in the Mako) I came pretty close to dying, and I actually did die a few times.
However, now, since I've kept all my gear and skills from the first playthrough, I've got enough health to stand up to a small army and, especially since the available equipment levels up with you but the enemies don't, a level 10 Spectre Master sniper rifle (that I could easily afford) with level 10 High Explosive Rounds that basically functions like a freaking bazooka, making casual headshots at 400m (though hitting the ground anywhere near them works too, so enemies in cover are a joke) and still easily beating out even the shotgun for short-range stopping power. One big BANG and basically anything's dead, while my armour can easily keep me alive long enough for my overheating to die down and I can fire another tactical nuclear warhead.
I'm breezing through the game now, no trouble at all. Admirable and understandable, keeping stuff after a playthrough, but since the enemies are as strong/weak as ever, it is pretty much horrifically OP.