No, you can't turn it off that I know of. Disabling drag would be a pretty bad thing anyway, IMHO. You might be able to change the distance before a click turns into a drag though...
It's not unique to the virtual keyboard. You can't hear two clicks, because the bounce is very quick. Try recalibrating the screen, using the lightest stylus touch possible; sometimes (including for me) that helps, though some people say heavy taps help for them.
But, it does have a backspace key for fixing those, in any case.
Not a problem, as long as you put your finger/stylus down without bouncing and start dragging immediately.

Hello all again. Wanted to follow up with the "double-tapping" issue for documentation-sake. Turns out that my touch-screen interface was going bad, and I just sent the N800 NIT unit back for repairs, too. I have since tried a new unit and I did not have the "double-tapping" issue, like I did before.

In case anyone else researches this subject matter, through searching the forums, here's what happened:
1) Touch-screen started doing "double-tapping" and "repeated clicks" on occasion. This was expecially noticable with the virtual keyboard.
2) Later, Touch-screen started to become suddenly and completely unresponsive, while the other keys still worked. A reboot or a removal of the battery for 15 seconds was required to regain functionality. Problem was happening with increasing frequency.
3) Called Nokia technical support, who diagnosted the problem as a connection issue. Sent unit back for repairs. Unit was 10 months old.

Truth be told, I used this device so often that it was dropped out of my hands or jacket pocket many times. It is very likely the touch-screen connection became loose or broken over time.

One popular tweek for the browser is to turn off "Fit To Page" which seems to slow things down and works perfectly well without it.

Search the forum for other information on this tweek.

I turned it off and never looked back.

There is no Java.
I built Lynx, but it's awkward/useless on complex graphical websites.
Simple websites work OK in the Firefox browser. So the only point would be browsing via a B/T phone with an expensive data plan - Lynx won't download images, stylesheets or scripts, so you'd save some money.

to stop the runaway scroller, just tap the block inbetween the arrows with the stylus. you can also scroll page by page tapping the space bar.