Considering that the 2004 is not much changed from the 2002-2003 models, it
would be safe to say that the current production model will likely be
similar.  When choosing the 2002 model and comparing the other makes, the
Altima's useable space was striking, compared to the Accord and Camry for
the price.  The Altima is a fairly big car for it's class and a lot of it
has resulted in large cabin spaces.

From a reliability/handling/safety standpoint, I believe any of your 3
choices will deliver adequate performance.  I have to admit that I "pushed"
an Altima rental (sorry about that Budget) up and down the slopes of
Haleakala on Maui and found that shifting the auto trans out of Drive and
into 2 and 3 was great.  Body roll was present on the stock suspension, but
nothing overly distracting.  The rear end is a bit light but the car, under
normal conditions, is predictable and after awhile, is "tossable."

The 2.5L 4 cylinder is smooth and responsive and probably the best choice
for a daily driver.  The 3.5L 6 cylinder is probably overkill, but it's not
much more money and will likely help on resale in its later years.  There is
also a "grin factor" when entering the freeway or passing a truck on the
interstate.

People either love or hate the styling.  The "alteeza" style lights may
start to look dated and the lack of a 2 door coupe version are also
commented on.  How long Nissan will utilize this body style without
refreshing is also a good question.

I faced the same decision 2 months ago and ended up getting the v6 Altima
(3.5SE) and I'm glad I did. It has a very large interior, largest back seat,
handles like a sports car and stops like a dream, and it is very very fast.

Good luck.

Robert