If they click then Drogba and Torres would be absolutely devastating. Saying that Drogba is 32 now and has what 2 years maybe left in him at Chelsea max. But when he retires i can see Chelsea playing 3 upfront with Torres, Kalou and Sturridge in a front 3 and that could be very good too.
Carroll has has a good half a season but moving to Liverpool will only improve him as a player and a man. Suarez is a tricky one because coming from the Dutch league you cant really judge. Former goal scoring machines in Holland such as Kuyt, Kezman and Afonso Alves all couldnt repeat their goal scoring ability in the PL (althouth Kuyt has re-invented himself as a right sided player he isnt prolific like he used to be in Holland). But then you have players like Van Persie and Ruud Van Nistelrooy who have been a success in England. In the short term i think Drogba and Torres will score and create more goals but Carroll and Suarez both have age on their side.