I haven't had the opportunity to even test if X11 forwardng through SSH works. (I assume your meaning is ssh forwarding. The X11 socket (port 6000) is not exported, so you can't just set the $DISPLAY).
However, I would suggest to use a VNC instead of X11 forwarding, as VNC works quite well. Don't know how good it would work with OpenOffice.
Yes, in general. I regularly run upto 4 programs at the same time. It's not the number of programs, it's how much memory each one uses. But those four, sure. No problem. You won't even need to enable extended VM (swap space). But watch out for the browser, that's where you can eat memory because it depends on what page you're loading.
You've heard right. As for youtube, there were improvements in one of the OS2007 upgrades, and some says it's even better in OS2008 - but that's second hand, I'm waiting for the official OS2008 release myself.
Quite well. The opera browser in OS2007 does Gmail perfectly, but the others maybe not as well (and not at all with google docs). MicroB is good here. But as already mentioned by jhoff80: No tabs. But you can open as many windows as you want, and switch between them. I had 15 open in Opera just to test. If it works or not depends entirely on how much memory the content in each window takes. Lots of pictures? Don't try to keep more than two or three up.
dblank already answered that one: Mplayer.
Buttons and screen locked is very much the same as when you "turn off" a PDA: It'll last some ten days before the battery gets a bit too low. That's about the same as my Palm PDA when I leave it in the drawer. But unlike a PDA you can actually turn off the N800 for real, then it doesn't use any power (or very very little, but you could even remove the battery..). And unlike a PDA the N800 won't lose its content when you power it completely off.
For normal use you don't turn it off though, you just lock the screen and buttons. And unlike a PDA you can choose if you want the wi-fi and/or the bluetooth to be kept on (with wi-fi connected and active it can still be running for up to two-three days, depending on the wi-fi access point to some degree).
If your campus is set up with proper wi-fi bridging, then no problem. That's how it's set up here at work, I can walk to any building and it stays seamlessly connected.
The osso-xterm has a list of shortcuts you can tap, in a little always-visible menu. It has 'ctrl' which lets you tap 'ctrl' followed by 'c' on the virtual keyboard. Other ctrl sequences have their own default entries, e.g. ctrl-p ctrl-n. But you can program this menu as you want it.
I run both an ssh server and client on my N800. There are two versions: dropbear, which is lightweight but doesn't have scp etc., and openssh which has what you would expect. Both works just fine in my experience. It is extremely satisfying to ssh into the N800 from your workstation..!
Yes and yes. But as long as the cable is in you don't see the cards from the N800 itself.
Not familiar with 'bashpodder', but certainly wget, curl, these applications are available. Just install them from a repository.
No idea, but then I have only a vague idea of what it even is..