I bought the 64Gb 3G iPad 2 last May in Los Angeles whilst over there working. I wanted to use it to store scripts, photos, rushes and edits and it does that perfectly.
It does absolutely everything I could want in a tablet and I won't swap it out for the iPad 3 unless I can get one free. The lack of Siri is a non event as I doubt I would ever use it on the iPad. On my iPhone 5, Siri is a godsend and I love it, Most everything that I would use Siri for, such as appointments, calendar events etc, will auto-sync to the iPad anyway, so it's just not a big deal.
Although the iPad 2 has been superseded by the iPad 3, I don't consider the 2 in any way an outdated device in the same way that a 2011 MacBook is not obsolete just because the 2012 model has been released.
I think the iPads 2 will be around and supported for a good few years yet and if you can get one at a great price then go for it. Of course, if the price point of the 2 is similar to a comparable 3 then it makes sense to go for the newest iPad.