The keyboard you crave has been around for a long time. It's called the IBM Model M.

Cheap plastic? No.
Nice tactile response? Yes.
Decent slope? Yes.
Stupid curve? No.
Expensive? No. Not like an Optimus, anyway.
Simply excellent? Absolutely.

You can find out everything you would ever want to know about these here: http://en.wikipedia.org/wiki/Model_M_Keyboard

I have a bunch of the different variants; even the 15 year old one still works great.

Form before function is hardly a new paradigm at Apple, but the MacBook Air really raises the bar.

Colin is right: perhaps the most egregious of the system's omissions and limitations is the lack of a wired Ethernet port. To be honest, it's the one peripheral I use on my laptop *every* single day. Why do I use it? Well, in some places wireless just isn't available or reliable; that includes places where wireless is nominally available, but is rendered unusable for technical or bureaucratic reasons (think: heavy-handed IT departments). And then there are those times when I have so much data to transfer that a real 100 Mbit connection really is the way to go. And finally, I'll usually grab a wired connection if one is available just to enjoy the battery savings associated with having my wireless transceiver turned off.

A lot of the MacBook Air's other pieces of missing or fixed internal hardware are excusable to varying degrees. No optical drive? So what. I've been using the same dual-bay laptop for over five years, and most of the time my optical drives don't even make it to my laptop bag, not to mention a drive bay. 2 GB of fixed RAM? It will likely be enough for general purpose computing over the useful life of the machine. Fixed battery? That's a bit less reasonable. I just got the fourth set of batteries for my aforementioned laptop this week, and a service call or laptop disassembly project wouldn't have been welcome. But no wired Ethernet? Simply unreal. Megahertz (which was eventually acquired by 3Com) figured out how to stash an RJ-45 jack into a space no taller than a Type II PC card over fifteen years ago with their XJACK connector; surely Apple could have found room for something like this.

The MacBook Air is clearly intended for a particular market segment that I'm not a part of, and I realize that sleek, lightweight and chic are all major selling points among that demographic. But, rather than approaching the balance of form and function as an optimization problem, they chose to completely favor form over function and old-fashioned good design. And that's hard to respect.