To answer some questions..
I know of no plans to have a diabolo event at Tokyo Worlds. It was only done at the world contest in Orlando because Stu and I put it together (mostly Stu).. the interest faded the last few years we did it and we both had less and less time to dedicate to it.
Diabolo has always fallen more into the realm of juggling contests than yo-yo, though a few players (Rei comes to mind) do cross over.
For somebody just learning for the first time, there are a lot of options. If you want to test the waters a bit, duncan phoenix as the price is fantastic and it gives you both the bearing and fixed options (full disclosure: I developed this diabolo for duncan)
If you want something a little nicer, babache finesse or henry's circus (can be a bit heavy). The only full-time bearing diabolos I recommend are the triple bearing sundia's but they're expensive.
The spinabolos have always had a high speed vibration problem.. they may have gotten a bit better over the last few years but they also use to crush their spacers over time as well.
Bearings are fine to learn on, but you'll grow out of them in time.. they make certain things much harder (specifically multiple-diabolo play and tricks like infinite suicide which rely on axle resistance).. and the upside to them is rather small.
The handsticks can change the game entirely, get good ones.. I typically suggest some sort of aluminum stick as the carbon fiber/etc can be a bit 'bendy' for me. The big thing is making sure you get ones where the string comes out of the end of the stick rather than the side.. out the side can snag, or more commonly, cause the stick to wobble/twist/etc when released.
Kyle