SRW is short for Super Robot Wars - a series of turn-based strategy games. Their plot premise is pretty simple: you take several anime series with giant robots, and mix their plots and settings into one thing. Add in original characters, units and concepts to hold everything together like glue.
The results are much, much better than what you'd expect. The titles are extremely enjoyable and offer a decent tactical challenge, too. Well, some of the games are really easy, but you can play them with an aim of unlocking secrets or something. And others are pretty damn hard, too.
One thing though: the series is almost exlusively in Japanese. There is a fan patch for one title, and two others were released in English. Other than that, it's pure Moonspeak.
But it does not matter for me.
Now, to L - it's the newest installment, obviously. Some people are really critical of it, but I am not them. I am almost certainly sure I will like this, just as I liked the previous title, SRW K (which also has its own share of criticism which I mostly do not agree with). It's for the DS. Prime32 linked a preview with attack animations, so you know more or less how the game looks like already.