Apple has shown their cards on how all three generations of the iPad are documented with names when you need to tell them apart.
The official manual lists the iPad as iPad (3rd generation) in the printed / PDF user's guide. This is the primary consumer facing naming convention since many products get "the new" treatment launch in printed, media, advertising and web sales. At some point "the new" goes away and we are left with the canonical names.
When you browse the store for iPad docks, the MC360ZM/A dock lists compatibility with the iPad 1st generation and the MC940ZM/A dock with the iPad 2 2nd generation and iPad 3rd generation.
To complicate things (it can never be too easy, can it?), Apple's support web site for manuals changes this terminology a bit. If you are logged in with an Apple ID and browse a few manuals - both the general ones that address iOS 5.1 on the new iPads and specific ones that address radio spectrum power testing and regulatory compliance - you will build up a slightly different list of iPads - akin to the sales names when you buy them from the online store and names need to differentiate between colors, carriers, and 3G/4G radio capabilities.
Now as to what makes sense here, I see two alternatives - the first being do we try to set precedent and use iPad for all general questions as well as for the current device. The downside there is some re-tagging will be needed and some user confusion will ensue. The benefit is one big tag to keep things together and make people with tag reputation goals and badges more likely to arise (by not segmenting the iPad questions). The other alternative is to leave iPad alone and general and to make up a tag for each model as needed. We can use synonyms to group things (say some use of iPad 2 (2nd generation) WiFi + 3G (Verizon) might be better pointing to iPad 2). This will also have some retagging when people don't tag correctly and some user confusion (but different users will be confused here).
Regardless - it looks like we'll need a tag structure something like:
- iPad (1st generation)
- iPad 2 or iPad 2 (2nd generation)
- iPad (3rd generation)