Hmm, since I suspect Tod is only partially joking. I'll call him out on this one.
You'll need to post some numbers comparing same bullet weights to convince me. In fact, I'm so
not convinced that I just purcased a 25-06 AI to give me an advantage over my long barrelled Swedish mausers in 6.5x55 (which is superior in all respects to it's runty cousin the .260

) shooting light and medium weight bullets.
As far as I can tell, a regular 25-06 will give you 200-300 fps more velocity with same bullet weights. Last time I checked 200-300 fps was about the differnce between a 30-06 and a 300 win mag. Look at 120gr bullets for example, published at 2800 for the 6.5x55 (let's just be real nice to the .260 for this comparison and pretend it can equal the 6.5x55

), and 3100 for the 25-06. And those .257 bullets are not exactly shaped like flying bricks either, their BC's are pretty high. At 500 yards the 6.5x55 shooting 120gr partition is -46 inches and 917 ft/lbs while the 25-06 with 120 gr partition is -39 inches, and 1018 ft/lbs. Clearly superior in both bullet drop and retained energy. For someone wanting to slap varmints, the 25-06's 75 gr bullets pushed at 3700 fps only drop 33.5 inches at 500 - nothing in the 6.5x55/.260 arsenal is that flat shooting.
If a fellow is wanting to go for bigger game most entirely (moose etc), then the 140's - 160's of the 6.5x55 would likely make it a bit of a better than the 25-06 for "real" big game. But, even though I'm being nice to the .260, but let's be honest and admit the .260 is really not meant for those long 160's anyway, and really starts to lose gas compared to it's clearly superior 6.5x55 cousin when shooting the heavier 6.5mm bullets.