Killigangog: Good point, what's the deal with Mario being such a successful brand? One might think after 30 years of jumping around with the same onedimensional character, gaming society moves on?
They have, kinda. In the late 80s and early 90s, Mario was
everywhere. People couldn't get enough. He had comic books, a cartoon show, merchandise in every form and fashion, cameos in tons of other Nintendo games, even a breakfast cereal. The marketing force behind Mario was every bit as powerful and far-reaching as that behind blockbusters like Halo today, if not moreso, and I'm not sure if there's another video game character that has reached the same level of pop culture saturation and recognizability.
I'm out of the console loop, especially the Nintendo loop, so I can't speak for how popular Mario games are nowadays or how much hype is behind them. I can say that his presence in pop culture has died down considerably, and that when I do hear news from console land, it's rarely about Mario. Wikipedia tells me that his games still sell millions, though, so I guess he still has plenty of fans. Old-school Mario fans are probably buying his games for their kids nowadays.
As for what made him popular in the first place - I was quite young at the time (SMB was my first game), so I can't speak with authority, but I would say that it was a combination of factors. Mario was pretty much the face of the new console generation following the 1983 crash, and of the new generation of platformers in particular. Simple controls, tight gameplay, crisp graphics, catchy music, and appealing, kid-friendly characters probably helped cement his appeal to a broad market. When the sprawling SMB3 came along with its traversable world map, tons of powerups and huge enemy and location variety, people lost their minds. Today it's considered a classic of the genre, with good reason.
Mario 64 was an absolute masterwork, the 3D platformer that showed all the others how it's really done. It was the last Mario game I played, though. It was the last core Mario game until the Game Cube, and by that point I was starting to lose interest in consoles. I don't know if his games are still any good or not, and to be honest even the classics are often overrated (as classics tend to be), but given a chance, I'd give a new Mario game a go.