Given that sometimes we write few lines in a day, what is the most that you guys have written in a full work day - assuming good code with few or no bugs and little at most debugging/rewriting?
I've never measured it, so I'm just making up numbers with no evidence*, but I would guess:
1000-3000 LOC/day == you're just typing all day without much thought
10-100 LOC/day == you're writing good code
*Your mileage will vary.
On average, even when not debugging, I don't write that many lines of code a day. Sometimes as low as 10, which leaves most of my time for thinking rather than typing.
Instead of banging out 1000 lines all day long to complete a task, you can probably think about it a little more and accomplish the same task with 100 lines (which is more valuable overall, because it makes maintenance easier in the long run).
My lowest LOC-per-day score was when I was assigned a random memory-corruption bug (which was actually caused by a buffer-overrun by the GPU, due to the VRAM allocator being buggy), which took over a month to figure out. After a month of debugging, the fix was 1 line of code, or about 1/20th of a line per day over that period There was also more than one of us working on the bug, so maybe the real score is 1/50th LOC/day each!
Also, the amount of typing you'll do also depends on the kind of programming that you're doing. If you're building a new API then you'll spend a lot of time thinking about architecture, and very little actually writing the interface based on those thoughts. On the other hand, if you've got a tight deadline, e.g. "we need to show this level at E3 tomorrow!!", but that level in the game hasn't even been started yet, then you might hammer out 1000 lines of poorly written code to script that level's events, for now.
Anyway, in the real world, good managers will adapt to your skill level and speed. I've always been assigned tasks and asked to estimate the time it will take me to complete them by myself (instead of being given the time-frame that the task will take by the manager). You and your manager will slowly learn how quickly you can complete certain types of features, they'll learn which parts of the game it's most useful for you to be working on, and your estimation skills will improve over time too. You'll improve at your own pace, and as you do, your new skills will be recognized with more responsibilities, bigger tasks, and hopefully, promotions