I'm not sure light weight is a good factor, except for carry. I believe balance is more important, up to a the point where one can't support the weight.
I love my X Series SIG's, but SIG's are heavy. Good balance, just can't consider them light unless comparing to say a CZ75Tactical Sport, which is very heavy, great balance.
I suggest you look at the H&K USP9Expert. It feels lighter than its real weight; has great balance, super match trigger and very accurate.