We'd get a better idea of what looks good if you put up some pictures, and a budget might help but remember that everyone has different tastes when it comes to modifications... I personally thing that "slammed" cars are dropped too far and look silly, but to some people they're the pinnacle of modified cars. Your tastes won't be the same as anyone else's, nor will everyone's advice be the same.
A drop to at least S-Line height will look pretty good unless you like your car to look like a range rover, bigger wheels are usually good. I'd do an S-Line conversion, if it's possible + within budget.
