Omaha, Omaha/8, 7 Card Stud and 7 Card Stud/8 are important!
Recently I played a game of Omaha high and a friend wanted to know why I wasn’t playing Texas holdem. I answered: "Well, I sometimes enjoy a change". The next question was right to the point: “Can’t you win more money if you play holdem rather than something you don’t play as often?” I didn't take the time to explain what I will explain here, I just told him it was just for fun.
I believe that if you really strive to be the best poker player you can be, whether you mostly play holdem or some other game, you need to have some experience playing all of the more popular games. I play some Holdem, Omaha, Omaha/8, 7 Card Stud and 7 Card Stud/8 in limit, no limit and pot limit. There are a number of reasons for this, but the most importantly all poker games rest on the same general principles and structure. My holdem game has greatly improved because I gathered experience in playing other games.
Partially this is due to the additional experience at the poker table, but much of it is learning the underlying theories and strategies that apply to all types of poker games. If you ever read David Sklansky, you know what I mean. He is likely the best poker author alive. However, his books can be quite difficult to read, especially for novice players. I read some of his books before I was a good player and I got little out of it.
After experiencing a variety of poker games and gaining experience, I read some of his books again. They make a lot more sense to me now. Any experience at the poker table will help you improve your game, but by playing a variety of games will let you understand poker at a deeper level. This helps you to play any variety of poker competitively, once you understand the rules.
Another reason to learn and play other types of poker is that some of the biggest games in Vegas and other casino towns are mixed games and not just holdem. Often there can be a long line to sit in your chosen game, but a seat is readily available in a different one. Why waste your time and wait if you can sit in a game right now?
So I recommend that you consider playing a few games outside of your comfort level. Just have some fun and likely you will improve your overall game. Of course you initially want to play them at much lower limits than usual.