Isn't jailbreaking risky?

Jailbreaking will void your warranty, open up your device to viruses and malware, and you will no longer get any support from Apple or these forums : http://support.apple.com/kb/HT3743

Why jailbreaking is bad:

http://support.apple.com/kb/HT3743

There are plenty of movies in iTune Store.

What generation is your iPad first of all ? Jailbreaking can sometimes be risky if you're using the wrong program. It may result in a frozen screen, viruses that slow the iPad down, and lag will start occurring more often. It may also result in wiping your iPad. I would recommend for you to wait until iOS 6 comes out this fall and get Siri from there since the update is coming with Siri and other cool features. I hope you do know that when an Apple device is jailbroken, warranty is automatically cancelled and Apple will no longer support the device. Hope I helped.

Yes you can download/rent movies from the iTunes Store. What i mean is that you can get Siri when iOS 6 gets released this Fall. This will be the next Software Update available. I would personally wait instead of taking the risk.

Siri will NOT be available on the iPad 2, even with the release of iOS 6.

Sorry my bad, the Siri update will be for The New iPad only.

You do NOT need to jailbreak to play non-iTunes store movies. Because of the language barrier (and the, generaly, substandard quality of Apple's HD encoder), I prefer ripping my own BD discs.My non-jailbroken iPads play them just perfectly.

The same stands for almost every file format imaginable. It's only in very rare cases (e.g., 24-bit or lossless WMA) that you do need jailbreaking to be able to play - everything else can be played back without JB.