1. Original Opening
This theme was used predominantly for the earlier, darker, and grittier episodes directed by Masaaki Osumi. Charlie Koshi provides the vocals in this clip (and the next three), sounding quite a bit like Bob Dylan. The gunfire, car crashes, and numerous explosions throughout really emphasize the action / spy-film like quality of the series (and perhaps act to remind the viewer that Lupin was not originally conceived as a childern's show). It is worthy to note that the footage from this opening actually originated from the ill-fated 1968 pilot film. The second opening which can be viewed here, also used lots of the pilot footage and acted as an introduction to the show's colorful cast.
2. Third Opening
Lupin III's third opening reflects the lightheartedness and madcap capers that would begin to dominate the series after Miyazaki and Takahada took over from Osumi. It has a high energy Latin flavor to it. All of the characters are additionally shown to work together more often, rather than against one another. The animation here is notably smoother here than the excerpts used in the previous themes because it came from the series itself, not the pilot. Miyazaki's redesign for Fujiko can be seen at 0:58.
3. End Theme
Motorcycles make everything cooler don't they? All joking aside, this end theme is a nice moody piece of Western influenced music with some background whistling in it. The animation is simplistic but suits the bare bones style of the tune. The text on the screen is Italian (most of the videos for Lupin on Youtube are in Italian, because Italians love Lupin.), but the lyrics are in the original Japanese. It's interesting that the series kept this somewhat melancholy sounding song even after it dropped some of its darker themes.
4. "Lupin, He's A Nice Guy"
This is probably Lupin III's most famous song due to its distinctively early '70s sound and rather unintentionally humorous English lyrics. Basically, it's just Charlie Koshi bragging about Lupin in odd ways. There are some scratches, skips, and sounds from the show mixed into this recording as the original was lost. The song usually played during the series after Lupin successfully pulled off some sort of heist or tricked Inspector Zenigata for the tenth millionth time.
5. "Scat Theme (Rebirth Version, Fujiko's Theme)"
Several variations of Lupin III's "Scat Theme" exist, but the one shown here is perhaps the best known. Hummed by Kayoko Ishu, this rock-blues piece was primarily used when Fujiko was acting manipulative, troubled, or both. It was used heavily in the earlier half of the series, reflecting its more mature tone and character driven conflicts. The footage in this video clip, syched to the music, mainly uses clips from the 9th episode, so don't watch it if your worried about spoilers. (It's about Fujiko's past.)
* I originally wrote this article on the 7th of last month, to follow up my review for the first Lupin III series. However, it was taken down yesterday for some reason, so I had to repost it.