LCD HDTV Buy Now

Hi I want to buy a 42″LG HDTV/LCD 1080P/120Hz because I want give away my 32″Philips EDTV/LCD 480P. Whats holding me back is that if I buy a new HDTV with 1080P/120Hz, I afraid that their will be a HDTV with 1080P/500Hz because technology they DO change. What is your advice? Thank you!