If you like fighting games or if you are looking for a good place to start, Street fighter 4 is the way to go. Be adviced though, for this game is hard as it gets. Your tears will quench your online opponents' thirst.
''You lose!'' ... get used to hear that over, over and over again.
That said, while the game is brutal, it is on the other hand incredibly rewarding.
While I highly recommend this game, future buyers need to know that the online experience on PC is not good at all. The user will most likely experience lag spikes during matches due to bad net coding on Capcom's part.
If you own an Xbox 360, I would highly suggest getting this version instead. While you have to pay a small fee in order to access the online experience, the community is way more condensed than its Play Station 3 counterpart and apparently the game is not as fluid on Sony's console. That said, please note that Capcom made promises about an eventual fix for the PC online experience. So far, the recent patch did not fix the issue, but one day patience might pay up...
If you still want to play on PC or if you want to get the game on Xbox 360, might I suggest getting a fighting stick; it greatly enhances the experience and quite frankly, it is way more easy to execute the techniques.
Here is a great place to start getting information:
You should check for the following subreddits on www.reddit.com:
Which character should you use in the beginning?http://www.reddit.com/r/sf4/wiki/newbietiers
Which fighting stick should I get?http://imgur.com/ShzcJyE
Can I play with a pad?https://www.youtube.com/watch?v=uEoILCo8H4I