I would go for the Standard Magnum, simply because the hisotry on "New&Improved" does not always catch on.

I agree with Moishe. Many of the new short magnum cartridges that are hot right now might not be around five years down the road. If I were buying a new rifle, it would be in a caliber that had already established itself as permanent fixture on the scene.
That fraction-of-an-inch shorter bolt throw is not worth the risk of having a rifle chambered for an obsolete caliber on your hands.

300 wsm has been around for 9 yrs and is not going away. do a google search and you will find a plethera of information and folks that enjoy firing a 300 wsm. The only reason I bought my 300 wsm 3 yrs or so ago was the fact that I got a M70 still produced in New Haven when they were closing down. Take a look, I dare say every major rifle manufacturer builds a rifle chambered in 300 wsm, there is plenty of reloading info and factory rounds sold..not a sign of a flash in the pan or something in danger ofbeing obsolete. The wsm's do have significantly more recoil..If the M70 I bought was in stock in 300 win mag I would have purchased that also so either way it is pure preferance...but the 300 wsm is here to stay

I think the .300 WSM will be around a long time, unlike some of the other short fat's.

I like the WSM cartriges- short and stubby like me.

Agreed with WA Mtnhunter answer above and A + 1 for you sir!!!The .300 WSM has some serious knockdown power= sectional density + velocity!!!

Short mags burn barrels really fast. Additionally, the ballistics of the 30 caliber round could never surpass the ballistics of a 7mm round. I would either go with a 7mm rem mag which is readily available and doesn't burn barrels or the .284 winchester bolt gun. I had a .284 winchester built for a bench gun two years ago and it is a nail driver for real. Some magazines drool over sub 1" groups at 100 yards. This .284 will hold 5 shot 1" groups to 600 yards on a bench!!!