I find that most keys are in "better" positions for general development, even in vim (I always use the arrow keys, not hjkl). Having the colon key right next to shit is extremely convenient, as the ability to one-hand `:qa` when I'm done. The dash/underscore key is infinitely easier to reach on Dvorak, which is immensely helpful when dealing with C and PHP code that tends to use underscores for variable and function namings. My only complaint is that the [ ] brackets are further away, but the gains I have from the rest of the layout more than make up for that inconvenience.
I also took the time to remap the physical keys on my laptop, and purchased a couple inexpensive mini keyboards (no numpad) that have laptop-style keys and were reportedly very easy to switch layouts, and I use one at home and took the other to my job. Having physically-mapped keys went a long way towards helping me out, and at least helps out anyone else who sits down at my machines.
Funniest Freudian slip I've encountered :-D
Once you type for a few minutes on a TypeMatrix (Qwerty or Dvorak), you come to understand the gross insanity of continuing to stagger the keys on a modern keyboard.
The TypeMatrix keyboards are switchable (via hardware) between Qwerty and Dvorak with a function key. I use X/loadkeys mapping most of the time anyway, but this is quite useful for boot prompts, BIOSes, and new installations.
As for learning Dvorak if you're already a fast typist, I like to say that it feels similar to how people describe quitting cigarette smoking (I've never had to do that personally). That is, for the first few weeks typing is a conscious process, and painfully slow (I got up to 20 wpm after just a couple days, but getting back up to 100+ wpm takes awhile). So what happens is that things come up, you have to send an email out quickly, or you need to debug some pressing problem, and you'll feel a powerful, visceral urge to switch back, just temporarily, so you can bang out the email or solve the problem. But you know you can't do that; you'll fall off the wagon.
OS X has a Dvorak keyboard map that switches back to QWERTY while you're holding down the command key. I don't know if there's an equivalent for Windows.