I know everyone's crazed about trying to find something similar to siri, but i'm still not sold on the voice activation gimmick yet. Does anyone remember when bluetooth first came out? I'm pretty confident I wasn't the only one who was freaked out seeing people walking around and looking like they were talking the themselves.
I've tried out some of the voice activated apps, but I think there are plenty of "assistant" apps that do the job well without voice activation. I can't be the only one who think's you'd look kinda dumb sitting on a bus and asking your phone to do random things.
My favorite "assistant" app so far has been something called Everfriends. It does pretty much everything an assistant app can do, but it actually has some personality to it by giving you characters that do stuff like tell you joke and find stuff for you. It's free, so in case you are interested here is a link to the android marketplace:
https://market.android.com/details?id=com.ifree.everfriends&hl=en