Prioritizing pads
 

After a few close calls to what surely would have been pain, I see potential injuries as I ride in the form of stumps, roots , rocks and off camber drops. Wondering what order you suit up (if at all) for XC riding? In the current heat wave it is hard to think of wearing more.

What do you mean by the order? What does the order of suiting up matter?

For XC all I recommend is chin/knee pads. Personally, I don't use anything for just XC, I worry more about prictacing balance so if I get stuck on an obstacle I can "track stand" and get over the obstacle.

Pads are for high speed meetings with the ground.

Heat can be remidied with hydration, pick up a camelbak.

By prioritizing I mean which protective gear do you consider more important and likely to be of some use. It seems to me if you can fall at an odd angle on a hard object from about 6 feet up, then that is high speed.

For XC all I would wear is a half nut (normal helmet :p) and gloves.
Here you are asking a Downhiller, I will put down my order.
Always a Helmet and Always gloves. Usually Shin/knee comb guards, sometimes body armour (usually if I am really wanting to punch runs or at a difficult track. I am however looking at getting knee dedicated pads with no shin protection whe I replace my faithful Fox 911's which now have a very nice crack on th eknee cup.

In order of increasingly likely crashes.

Knee-shin.
Then full-face helmet.
Moto shorts.
Ankle guards.
Armoured Shorts under moto shorts.
Full upper body suit.
Spine protector
Wrist guards.

It might not make total sense in terms of protection (i.e. having the wrist guards last when I've already broken a wrist snowboarding), but it's a compromise between being totally armoured and rideability.
In cold weather I generally wear more as well.

In the Don valley on the stunt trails I usually wear the first three as a minimum, unless I am just cruising through on the XC bike and avoiding the man-made features.

For protection, I wear a helmet.. thats it.

For xc helmet and gloves. Thats a given
For some of the more technical xc and lower end fr trails I will do shin pads.
For dh upper body and shin.