953 is another option. There are many opinions out there about this steel and the available tubing made from it, but there is no doubt that it is an extremely strong material.

Of the ones you mention, I would go with 853, probably oversized (more stable, less likely to shimmy).

Dent and fatigue resistance is much higher with these steels than with standard 4130.

Co-Motion chose 725 for some of their tubes, in part because 853 was not available in the same range of tubing diameters and thicknesses.

There are some other hardened stainless steels, besides 953, that might also be worth a look.

If you have the time and inclination, it might be worth going to http://www.mtbr.com/reviewscrx.aspx and reading through some of the reviews of bikes made from 853 and other materials. Some of those guys are very hard on their bikes. There are some 853 reviews that talk about how much better the steel held up through all the abuse. The paint was scratched and dinged, but the tubes didn't dent nearly as easily, and the bikes could simply be repainted.

I've spoken with frame builders who have torture tested 853. They say the difference is huge between the standard 4130 and the 853, which is extremely tough and resilient.

http://www.roadbikereview.com/ might also have some interesting reviews, although the hardcore mountain bikers' reviews might be more interesting and useful.

Some of the steels are easier to weld than others, some stay stronger than others after welding, and some even strengthen near the welds.