If you want beautiful awesome graphics, get NFS 4. If you want outrageous
driving, something different, get Driver.
NFS 4 is really beautiful, but after driving the courses a few times, you
are left with a game like there are many others.
Driver is something totally different. It has some nice sub-games (I like
the pursuit game the most: the main part of the game is quit frustrating,
but if they'd sold the game with sub-games only, I'd still would have bough
it!).
After driving through the streets of Driver (or Midtown Madness), NFS 4 (and
all other arcade games with the old fashioned tracks) becomes quit a
claustrophobic experience. I don't know what driving games you already got
on your computer. If you already have some old fashioned (arcade) racers I'd
recommend Driver. You can always buy NFS 4 cheap, because the follow up is
coming soon, and I expect this game in the bargain bin within a few months.
(Well, nowadays almost EVERY game can be found in the bargain bin within
months, but if you want a game NOW, I'd recommend get Driver.) Much more fun
for your bucks.
BTW There is an excellent Driver Configuration utility (free) which enables
you to create your won missions: very cool!
Jeroen