The g31s will overclock as well as the p35 boards if you have the onboard video disabled. They wont take much if you are using the onboard video though- maybe a 20% overclock is max. I've used all these boards over the past year but the one I have used the most was the G33-DS2R because of all the internal headers for usb and firewire. Part of my sales pitch is multiple front usb ports that are easy to get too compared to cookie cutter systems.
The G43/G45 equivilant has been shown at Cebit and fits my needs perfectly. I am sold on the "ultra durable" boards because of the all solid caps etc... . I open up two and three year old systems every day with blown or bulged caps with mysterious spontaneous reboots or other motherboard goblins wreaking interemittent havoc on the systems.
Asus is probably my second choice because the model you listed is all solid caps too but I've had bad luck trusting Asus since the early P4 days. Anyone remeber the P4PE that liked to reboot just any old time, and Asus saying theirs nothing wrong with them? Attitudes like that have cost them alot of my money in the past 5 years and I'm really not over it yet!

MSI's seem to be built ok but I haven't really tried any of their newer boards lately.