What black opening should I play?

Since you don't know when to use WHICH or WHAT ("which one?" "What do you want to do?"), I'd say chess would be a waste for you.

As someone with his degree in English...your criticism is useless and your conlusion much more idiotic than anything he could have said. "Which" and "what" have been used interchangeably for centuries in conversational settings. "What do you want to do?" could just as easily be rendered: "Which activity do you want to do?" Any question you can ask with "what" you can also ask with "which" by placing immediately afterwards the noun that had been substitued by the pronoun "what".  Furthermore, simply dropping the word "opening" (so that it now reads, "What is best for black?") would have made the sentence structurally sound in an academic, formal setting where information is simply being stated (such as in a thesis). And, given the context of the paragraph as a whole, his meaning would have been understood. But forums are conversational English, and different rules apply in conversational English. In English, when a speaker is seeking immediate response, and especially when seeking a specific response, it is the responsibility of the one asking the question to make himself properly understood by giving as much contextual information as possible. If you ask "when" an event happened, the person answering your question might tell you "after I got home", but you really wanted to know the specific hour. The person responding answered your question correctly, but did not give you the answer you sought. Therefore, when speaking conversationally, the need to give as much context as possible far outweighs the importance of perfect structure. When speaking conversationally, we often interject additional words or phrasing because of this. So, "what is best for black?" is structurally correct, but while he is "speaking" (with a keyboard in this instance) the speaker may vary well give more immeidate context by inerjecting "opening", clarifying which noun the pronoun "what" referenced. In fact, we could leave his sentence wording unchanged. Simply add some parenthesis and we get, "What (opening) is best for black?"; though it looks awkward, we technically could even use commas, as they are allowed to be used for parenthetical phrases: "What, opening, is best for black?"

So, please do not pretend to have an authority on language when you obviously do not understand it's finer points yourself. While we are on the subject of your lack of understanding of language, if we are to judge by your conclusion, "chess would be a waste for you", you apparently recognize neither the depth and complexity of human language, nor the fact that it utilizes a completely different type of intelligence. Language is infinitely more complex than chess. We have taught animals whose communication abilities are far lower than humans how to play chess. We also know of humans with syvant syndrome whose language and communication are severly limited, but who excel at chess, mathematics, music, and a host of other things at levels that far exceeds the rest of us who can communicate quite clearly.

Now that I'm finished with my rant, time to answer the OP. 

I think if you want to play aggresively, you should stick with the Sicilian in response to E4, just spend some more time learning it so you can better implement it. It is one of the most aggressive openings black has (black, by nature of moving second, is from the beginning 'reacting' to white, but in the Siclian he reacts by starting his own claim on the center with what is essentially a flanking maneuver instead of riding out to meet white head on).