You could do a lot worse than invest in another G10, unless you have experienced problems with game playing on that? You didn't say what budget you're working to, which obviously has a great bearing on your options...
In my opinion (though I have little experience of WHF's current fave 42" LG LCD set), I still think the 42" G10 represents one of the very best deals around at the moment, and is probably cheaper now than when you bought your current TV. V. fast response time on the 'game' picture present makes it a great TV for gamers...