I just the GOTY Edition on black friday, and am about to start the game. I was thinking about a stealthy but lethal play through, but that's just going off of what I enjoyed in other stealth games the most. What do you guys recommend?

First of all, you'll be using a lot of stealth regardless of your play style
But I think I know what you're asking. Low Chaos or High Chaos.

From what I have experienced, playing "super-sneaky with as little combat as possible" is more of a challenge than "using all the different weapons and killing whenever you can."

My first playthrough was very stealthy with as few kills as possible (Low Chaos)

In my second playthrough I killed a lot more people and didn't worry about raising alarms and fighting all the time. (High Chaos)

Low Chaos requires more planning, time, and reloading if you make a mistake.
High Chaos was more fun, because the weapons can be used in so many crazy ways, and the game is more fast paced.

Both are great, but High is easier.
But you should just get in the game and see which tactics suit you best, and go from there. You can use a combination of both just fine.

My suggestion for the first playthrough would be, regardless of your chaos and kill level, to turn on objective markers (though don't hesitate to turn them back on if you're stuck, there are a few places you may need them).

My first playthrough is about what I think is realistic. I try to be stealthy but when I kill a man I don't reload and I just deal with whatever chaos I end up with. Being stealthy and non-lethal is generally more challenging and immersive in this game.