A great game ruined by being poorly ported to the PC.
The first game isn't needed to catch up on the story. In short, your character was involved in an explosion at the end of Saints Row, and has been in a coma for several years. Upon waking up, you escape from prison, and start your mission to re-build The Saints gang and take back the city. Not a deep or an involving story, but that's to be expected from games like these.
The characters are all different and have their own personalities. Everything has charm in it. Everything can be customized. Everything can be done. Feel like sky diving in the nude off a building? Go do it. Feel like running around shooting hookers in the face with a shotgun? Go do it. The amount of customization is crazy. Cars, your character, the gang, different cribs, and more can be customized to your tastes.
Sadly, anything other positive I could say would be a lie. The PC port is broken and unstable. There is no guarantee it will run on your computer. Even if you have beyond the requirements, it may not run. The game will stutter, stop, load, run smooth for a second, stop, stutter, load, and repeat. This makes the game impossible to play through high speed chases and intense fights. It may run fine on your computer, or it may not. There is no fix for it either. It's due to the bad coding of the game, and there won't be any more patches for it. The last one was released last year, and didn't fix the problem.
Among that, there are other things that ruin the PC port. The sound will only come out of the left speaker when you play. To fix this, you must go into Window's settings. Hitting shift and control move around the menus, instead of right or left on the arrow pad, or just using the mouse. This makes it extremely awkward doing anything beyond gameplay.
There are also certain keys which cannot be replaced. They are not shown on the control pad, so if you accidentally replace one, it's gone forever.
Saints Row 2 is truly a fun, and great title, and a must have...for the PS3 and Xbox 360. The PC version is just flat out broken. It's a gamble to whether it will work or not. Again, there is no fix. Nobody has been able to make the stuttering stop. I haven't played this version of Saints Row 2 for long because I physically can't. Neither can the hundreds of others who bought it in yesterday's sale on Steam. It's ridiculous. Save your money, go buy the console version.