I have carried many things on my stock rack for the better part of 4 year without an issue. Everything from a fully loaded raft and oar frame (I would not advise this) to firewood, fuel, sheets of plywood and even 20 2x4's. I carried my hi-lift and shovel year round in a thule snowboard rack mounted to the stock cross bars. That being said I decided I wanted a more versital rack so last week I installed the Gobi Ranger with shovel/axe mount and hi-lift mount. I have to say I love this new rack. Both for quality and looks. I know it will come in handy with everything I tend to put up there.
I would say its up to you. I think the stock rack will do what you need it to. May need to add another basket. However if you have the money I would suggest the Gobi. The Calmin rack is nice, and well made as well, however I do not like the fact that you can not use the front portion above the drivers compartment. But then I don't have a sunroof.

Hope that helps.

Casper