Ok, there is a TON of confusion about Voice Recognition right now. I strongly encourage you all to read my post to try and clear a few things up.
First and foremost, Google Voice Search and Google Voice Dialer are not intended fixes for the Voice Recognition issue. Plus they are being beta tested in select markets, making them unavailable for the majority of the Marketplace.
The problem with Voice Recognition on the Hero is that HTC did not include the android.speech package in their ROM. I have been personally trying to work with HTC to fix this issue, but very few (basically none) of their support staff know near enough about development to understand a thing I say to them. I've been slowly working my way up the ladder for the past few weeks.
All of the Voice Recognition features rely on a service included in the Android OS, but HTC had it removed (I wish I knew why). The reason installing apps like Google Voice Search fix the issue is because those apps will also install parts of the android.speech package necessary for them to work. They do not install the full Voice Recognition Service though and cannot be relied on as permanent fixes.
I can only assume that HTC will (and is) working on putting the android.speech package back into their ROM, but as I have yet to get in touch with any of their Android Development team, I really can't say anything for certain.
I am also trying to encourage an independent Android Developer to help the cause. There is an App on the Marketplace called Enhanced TTS Library. I am hoping that with enough encouragement, this developer will be willing to create a similar Enchanced Voice Recognition Library as well.