You want navigation in your car and don't mind paying an ear and an eyeball for the stock navigation system (in reality, $2000+), be my guest and ignore this thread! Also, enjoy your stick figured roads!
Benefits:
1) It's already in the car when you bought it, just sign and drive... hehe.
2) The wonderful control stick next to the shifter (I wish I had that

)
3) If something goes wrong, take it to the dealer and bitch that you sold your ear and need to wear an eyepatch for this and want it fixed!
Bene-nots:
1) Expensive as I already eluded to
2) Some people say it's subpar to Garmins, but that's all opinion.
3) Depending on when you bought the car, an update is probably available these days, and you can't just download it.
So, with the demand high in aftermarket solutions for navigation systems, a lot of us are willing to hold off on the stock navigation (prices usually being the big factor), and wait for another solution that's cheaper. Well, here are some solutions:
OEM-knockoff Navigation popup screen (Motorized) w/ Garmin Unit in Glovebox - Cost: apprx $1000
Links here:
OEM Screen,
Garmin Unit
Japanparts.com Navigation Mount/Tray (Manual Operation) & Coolnavi 700 (or similar) - Cost: apprx $700
Links here:
JapanParts OEM Nav Manual Mount,
Coolnavi 700
Double-din navigation solutions with radio and multimedia extras - Cost: approx $1100
Single-din motorized pop out Screen with Navigation features - Cost: varies, but usually $700-1500.