Hmm...more than a few people here started with Klonoa 2, based on a quick scan. ANYWAY, my interest in this series is a complicated one- you see, back in 2001-ish, at what used to be my Toys-R-Us (now a pet-smart T.T), they had a demo for Klonoa 2. (interestingly, this was also how I was introduced to Sonic Adventure. But that's another story.) I tried it, fell in love with it, and never saw it again for some time, without even knowing what it was called, vowing to myself that someday, somehow, I would get a PS2, and find this game again. Fast forward a couple of years (or months, a child's perception of time is often fuzzy), I have a PS2, a couple of games (Aqua Aqua was my first, followed wome time after by Okage:Shadow King and Dark Cloud.) and there, at Hollywood(a videogame/movie rental...was eventually converted into Play-N-Trade, then to a friggin' birthday party hair salon...T.T), I saw it...one floppy eared, adorable little cat-rabbit riding a surfboard. Then, I knew- There he is...the video game character of my dreams. Of course, I played the game as much as I could, but when it came time to return it (I used to rent almost ALL my games. a practice I pretty much gave up completely after renting Super Paper Mario- another story) I was heartbroken. But, sometjing I did afterwards was...well, something I regret- I had a chance to buy the game from Gamestop, but I said no, because I assured myself that I had played enough of it, to fully keep the experiences with me. And i never saw the game in person until 2 or so years ago, at another gamestop. Soon after I played Klonoa 2, though, I happened upon one of the best discoveries ever- Klonoa:Empire of Dreams. I though, at the time, that it was the first Klonoa that was alluded to in Klonoa 2's title (If there's a Klonoa 2, then where's Klonoa 1?), but that wasn't important- what's important was that I was finally reunited with my favorite videogame character ever...next to Sonic, of course, but it's still a close call. (actually, one of the reasons I loved Klonoa so much may have been because the game reminded me of Sonic Adventure. What can I say? I have a soft spot for gamecube/dreamcast/PS2-era cell-shading/graphics.) So there you have it- Klonoa is the entire reason why I own a PS2 in the first place. I inadvertntly owe a lot to that game...Dark Cloud, Okage, Katamari Damacy(technically, I owe Toonami for mentioning that, but that's another story), Sly Cooper, Final Fantasy X (my first Final Fantasy, too), Shadow of the Colossus, Psychonauts, Metal Gear Solid 2, Kingdom Hearts...all because of that one store demo...
TL,DR:Toys-R-Us store demo was what got me hooked.