First of all, hello everyone. I've been reading for a long time, but this is my first post. I hope I can help, this is a great community.
I'm using a t60 as well with an X1400, Gutsy...
So far, what's been working for me is the 1650x1080. I find it appalling that I have to be happy for something so trivial, but what can I do? Like a lot of people here, I will not buy ATI again, unless their drivers become OSS.
Now, when I start compiz, I just get a white screen. The cube works and rotates, reflects, but it's completely white. What helps me is doing this:
Code:
sudo rmmod fglrx
cd /lib/modules/*/misc
sudo insmod fglrx.ko
modprobe fglrx
after that, compiz works, and works pretty well, except for the firefox scrolling bug, which is still here.
EDIT: Actually compiz lags a bit when I have more than a few windows open, especially if one of them is firefox.
also, as for video, xv looks horrible, and opengl cannot handle fullscreen (i get maybe 5fps). this is using vlc, but i don't think it matters which player I use.
Does anyone have any tips on not having to do that whole DRI enabling thingie everytime i boot? Something i can do?
Also, suspend/hibernate do not work for me at all, again - haven't ever worked in gutsy, to be honest 
Another problem that I've been noticing is the very high temperature of the card - around 57C without compiz and 61-62C with compiz. Using the old fglrx drivers, I used to get 45-46 with Compiz/Xgl. This is a very serious issue for me, the fan is running at level 7 (full) all the time, and I am really not happy with that.