There's a big Apple event tomorrow to announce the new iPad. From the rumours, it'll be almost identical to the iPad 2 except with a "retina" display and possibly a better camera. Which is why I believe that it will be announced as the "iPad 2S" Apple has two types of product announcements: revolutionary, and evolutionary. Revolutionary products really shake things up; they are either all new products or vastly improved versions of older productions. Evolutionary products, on the other hand, are small, incremental improvements on existing offerings.
Apple has an established naming convention when it comes to evolutionary iOS products: it's the old product name, followed by an S. iPhone 3GS and iPhone 4S are the two examples. These featured only modest improvements in specs, though they did have some of their own features (like Siri or the 3GS' compass).
The new iPad is going to have almost identical specs to the iPad 2, just with a new display. Yes, it is a big, important feature, but it's only one feature. Siri is a huge feature - the ability to literally speak with your phone - but it only earned the iPhone 4S status as an "evolutionary" product.
The iPad 2S will include a retina display and new graphics hardware to support the screen. Maybe a better camera. Literally everything else about the product will be identical from a consumer's perspective.
I'm not going to justify the "iPad 2S" name anymore - everyone else can justify the "iPad 3" name.
(As for "iPad HD", please. That's so crass - this is Apple, not Samsung.)