Possible consideration:
I've noticed on my various iDevices (including iPad 1 and 2, and several generations of iPhone and touch), that each firmware upgrade seems to tax RAM more (general slowing of apps, more freezes or crashes). And with each firmware upgrade, developers update their apps to take advantage of new firmware features.
Knowing that, I would recommend getting the latest model iPad for its 1GB of RAM and other improvements of its innards over iPad 1 and 2. Also, with each latest model of any iDevice, you stand a better chance of longer firmware upgrades.
Word is, iOS 6 is just around the corner. iPad 1 won't get that firmware upgrade. iPad 2 will get it, but not Siri. iPad 3 will get the whole package. You might not care about a specific feature like Siri, but I mention this to offer context that might help new buyers decide. (When I buy any device, I consider current features, as well as lifespan of hardware, firmware and app access.) Also, with each firmware upgrade, developers are generally less apt to keep supporting older versions of apps. Depending on what apps you use, that might leave you with fewer options on iPad 1 or 2 vs. 3, for example.
If I were buying now and choosing among iPad 1, 2 or the new iPad, I wouldn't hesitate to get the latest model. If money were tight, I just wouldn't get an iPad.