Yes. If you like FPS games and RPGs, then DEFINITELY yes! They are both pretty cheap now and good games in their own right. I I would say BL2 is the better of the two games and improves on the first game in pretty much every way, but they are both good in their own right. BL is a good game and it is kinda important to understanding the backstory, characters, and locations in the series as a whole.
These are the type of games where the story keeps you interested and the loot keeps you going, if that makes sense. lol Both games have an expansive story mode and will take you a while to complete. I haven't played it but I've heard the DLC for the most part, adds a lot of great side stories to the game as well. It certainly isn't a requirement to enjoy the main game though.
The biggest enjoyment I got out of this game was definitely the local co-op. It was probably in my top 3 local multiplayer games for the last generation of consoles.
Borderlands is only pretty cheap ($8 (360)/ $10 (PS3)) on Amazon so I say try it out. If you like it, get Borderlands 2
Hope this helps!