There are many great games available to play at the casino. Different people enjoy different ones and so it is quite a personal choice.
If you have never played at a casino before, then it is a good idea to observe the games that are being played there. You will be able to get an idea of what they are like. You need to understand how to play them before you spend money on them. If you are playing online then you will find that there are websites where you can learn. In you are in an off line casino then you may find that they instructional sessions where you can learn to play a selection of the games on offer.
You will also need to decide whether you want to play a solo game, such as slots or whether you would prefer something where you play against others, like poker. There are also games, such as craps, that can be easily observed and you might enjoy that, but you may not.
You may want to play something that you have a better chance of winning. To do this you need to understand how to play the game and know some tactics. Also certain games have bigger prizes than others and the odds are better on some than others. High stake poker games will provide big prizes, but they may only be open to experienced players and professionals or you could be against very experienced players. Some slots have high jackpots, but the odds of winning could be low. Other games may have different prize funds, depending on how many other people are playing.
So what you consider to be the best casino game will depend on which one you are best at, which one you are more likely to win or the atmosphere of the game and so it is worth giving it some thought.