I'll go out on a limb and say the SF4 Tournament stick is definitely worth getting. Haven't had a chance to use it myself, but the man who was responsible for putting it together is probably the most hardcore stick-er I know. He runs the 'SDTekken.com' site which keeps a pretty good technical list of arcade sticks, all of which he owns personally.

As for that Street Fighter video... Daigo and Justin clashed twice this year in Street Fighter 4. The first was during the Gamestop tournament at the beginning of the year, where Daigo utterly trashed Justin. The 2nd one was at the 2009 Evolution tournament--the same venue that that SF3 video took place--and it was an intense, intense battle.

VF4 Evo is worth purchasing for the training dojo alone. It was released brand new in '03 for $20, and I've seen 'brand new' prices for it for around $6. I understand that Vivi isn't into it, but if anyone else reading is interested in getting into or learning more about fighting games. Seriously, it is far deeper than any other fighting game. It teaches you exactly how to do things like 'Evading Throw Escape Guards', the difference between a full spinning attack and a half spinning attack, how to deal with specific types of combat situations, when and when not to throw, things like that. The fact that it actually shows you the exact inputs and the timing of such, and even provides performance-based suggestions if you fail at it makes it almost feel like you're actually learning a martial art. I can understand if it doesn't click with you though, after already having played it. VF5 in particular was pretty barebones, which doesn't help with its accessibility.

This video shows part of that mode, where after it teaches you how to do the 'evade/throw escape/guard' it tests you on it.