If your car has the original springs, you need new ones, if you wish to maintain the proper geometry and intended ride quality. Yes, it'll likely raise it a bit, but shouldnt be too much. However, there are MANY manufacturers and options, so if your car had no AC and a straight six from the factory, and you put big block Chevelle A/C spring in it, then yes, you'll raise it a few inches.
Get the springs that you want, not what your car came with!
Bilstein shocks will give you the best ride available. Yes they cost more, yes it's worth it.