Let's take it one at a time:
RWD
You're still pretty young from what I've gathered from your posts, your parents are buying this car for you right? I'd honestly say to just a FWD car, simple and easier to predict. (Enthusiasts, please don't argue on this unless I'm wrong talking about the *general* population) In just daily driving to school/work/grocery store/etc. you probably won't notice a difference. Do you feel a need now? If you did, you probably wouldn't be asking and so that's why I recommend a FWD car. If you notice a difference in that basic driving, and very possible depending on what roads you take, ramps, just having fun on the way, etc., then yeah, no question about RWD. As I just said though, if this was an issue, you wouldn't have even considered a FWD car.
loaded (Leather/Sunroof/BOSE/etc.
Is a sunroof not available on the Altima? Getting into a bose setup might be a hassle if you ever choose to change it - do a search on why and I'm sure you'll see the reasoning. Leather seats are an option on the Altima.
much more parts available (it's a sports car)
What are you looking for? What exactly is lacking in availability/production in terms of the Altima's aftermarket? Don't just make a generalization, point out exactly what's holding you back.
Infiniti badge (resale value)
What? If we're comparing percentages, then I don't think the brands would be very far apart, but I quickly searched and wasn't able to find numbers. I'd say that they'll both be similar unless you're comparing new vs. used in which case it's an independent comparison of the two cars you chose - a new car will take a bigger hit, no doubt about that.
made in Japan (quality higher than products made in USA)
Is that a fact? Can you point me to an article or study that shows this through data and reasoning?
original looks (the Altima coupe uses its basic design)
If you feel the G35 looks better, +1 point for the G35.
Insurance will probably be higher on the G35. How does gas mileage compare for both?
How about a used Altima? If a new Altima with leather, sunroof, etc. is too high of a price, a used one may be a good option.
Again, don't remember your age exactly, but you're either going into college or you're already a college student, right? Either way, you're probably going to end up having friends with you a lot it would be a lot more convenient to get a sedan. You'll also have a bit more space and be able to utilize the area better in a sedan. If you'll be going between home and school, this could be important.
I'm speaking simply from a practical point of view and an objective decision based on what I've presented. These are 2 very different cars, and so I'll say the same thing I believe I've said in your other threads: Figure out what you want from a car and come to an agreement on that with your parents. Pick a price, whether a used car is an option or not, and then start looking. Go test drive each of the cars and make a good decision.
Figuring out what you want from the car you're going to buy is the first and probably most important step. You've had threads on the Civic Si, S2000, VW GTi, etc. and my conclusion is that you don't have a definite idea of what you want. Define what you want from a car that your parents agree with and make your choice.