Your 4 opening choices

To play chess w/o an opening repertoire is to ignore the mountain of acquired chess knowledge accumulated by the people before us. Yes, you can play chess w/o an opening and defense system, but don't expect to get as good as you could w/one. If your goal is fun instead of quicker improvement, then it's fine to play this way. But, to advance up the Elo ladder, it's pretty much accepted that you should develop an opening system and stick to it for a while. You may think it's not exciting to play "the same" chess always. To me, it led to a deeper understanding of the game and showed me how dissimilar and exciting chess can be. I started winning more, too. Some people will say that they've learned more about chess by just playing all the time, through their experience. That logic rarely works in this game and I'm sure it can be proved otherwise. So, what I'm saying is, developing an opening repertoire is probably a good thing. You'll need 1 opening as White, and 2 or 3 defenses as Black. As Black, you'll need a defense for 1.e4, 1.d4, and 1.c4 & 1Nf3 (anything else [e.g., 1.b3 1.g3, etc., will probably eventually fall into one of the above choices.]) Sometimes one defense will work for 1.d4 *and* 1.c4 & 1.Nf3, so that's why I say you can get by with 2 or 3 defenses as Black.

How do you pick an opening system? One step is to find out your style. Do you like to play aggressively or solidly--for White and Black? Once you come up with your answer, go to the following link and see what they recommend for you:

http://www.exeterchessclub.org.uk/Openings/4choices.html

Very interesting reading. And even if you disagree with the advice above, which is not mine (I just agree with it), you probably can't hurt your game by adopting an opening system. I believe your games won't be less exciting, you'll probably start winning more, and consequently your Elo will go up. Try it. I've stuck with it for a year, and it's worked quite well for me. I want to pass this along, hoping you'll have the same experience.

Exeter is a useful site. To put things in perspective, Exeter Chess Club recommends the above handout for players rated 1500-1699 USCF. For players <1500 USCF they advise:

"(Don't spend a fortune on specific monographs until you are committed to the line; you are better off owning more general, inclusive titles until you pass [1500] ELO (Class C).) Reuben Fine's The Ideas behind the chess openings is a great place to start, but it is terribly dated. (He disparages some openings which, fifty years on, are believed to be very playable.) If you have access to this book, and can bend the ear of a couple of players who are a couple of classes or more above you, this is probably all you need. "

I like "The Ideas Behind The Chess Openings", but if you're looking for something shorter and more modern you may also like "Improve Your Chess Openings" by Chris Ward. 

I hear a sentiment occasionally that I paraphrase as "I play to have fun, so I don't study openings." I have to wonder, is it fun to continuously play moves that are well known to be inferior? I played a dozen or so blitz games with someone online recently who continuously played the same wrong opening moves with black. After the second game I wrote him a message to the effect "on move such and such, don't let me play move X." But sure enough, the next 3 games he played again right into the same line. He tried different things after that point, but it didn't matter as his position was already hopeless. I can't imagine it was all that fun for him. In short, his refusal to learn an opening idea probably made the game less fun for him rather than more fun.

One way to think about openings is to imagine "what if you could show a position from your game to the best players in the world and as them what they would play." In the opening, you can do this! Of course, you also want to ask them "and why would you play that?" 

 I couldn't agree more.

 That's the great thing about correspondence chess: you can use opening books while you play. I've learned a lot from using them. This has positively affected my over-the-board play. I understand the point of the moves, and know the ideas and the long-term strategies involved in my opening choices. Knowing just a few openings doesn't limit my chess. It had the opposite effect for me. It's like once you learn more about something, then you realize how much you really don't know. Chess was this way for me when I started. I knew how the pieces moved and how much each piece was roughly worth. But after I started reading tactics books ('Understanding Chess Tactics' by Weteschnik is great), endgame books ('Silman's Complete Endgame Course' is fantastic), and other books ('The Amateur's Mind', 'My System', etc.), I quickly realized how much I didn't know. Chess became something *way* beyond what I thought it was. My game experience has become more meaningful and fun.