It is looking very much like Chelsea will have the attacking options of Hazard, Mata and Hulk. The only question that will remain is the center forward or central striker position. The options available to Chelsea right now, after the release of Drogba, are Fernando Torres, Daniel Sturridge and Romelu Lukaku.
My thoughts are the following: if Chelsea want to stay in the mold of Roberto di Matteo style of football, then they will need to buy a striker who can be big, hold up the ball, as well as combine well with the wingers. Torres is not really a play who can play with his back to goal.
Center forwards out there: Ibrahimovich, Cavani, Llorente, Falcao, Adebayor, Ba, Kone, Remy - the list is long. I think that Llorente, Falcao and Cavani would be the most likely buys for Chelsea in terms of age/price/willingness to sell.
If they go the Guardiola route then he will mots likely want a technical center forward and not put too much stock into size and hold-up ability - which means they may as well keep Torres.