swamgunner:
Welcome to THR! It's a great place to hangout.
As to your new rifle selection, I have owned a Weatherby Mark V, in .257 Wea. Mag., as well as other Wea Mags: 270 and .300. They are awesome rifles, and awesome cartridges. However, as you observed, they too are over-priced. Point of rationality, meaning to get the most performance for the least money, Weatherby Magnum fails the balance of performance to cost.
As to other cartridges you mention, the .270 Winchester and the .30-06 Sprg are awesome, especially given modern propellants. The .30-06 Sprg seems frequently to be under-loaded in factory rounds, due to the chambering being offered in some many autoloader firearms. The .270 Win doesn't seen to experience this ballistic anemia to the same extent.
I reference specifically, Hornady's "SuperFormance, 130 grain, SST, with a muzzle velocity of 3,200 FPS. They drop deer dead-right-there. If you desire greater penetration, Hornady offers this same cartridge in the 130 grain GMX. The GMXs are guaranteed to fully penetrate any game animal in North America. And they do! I have used them in my Weatherby Mark V, .300 Win Mag.
Since you already have excellent rifle choices, this rifle can be a "just-because" rifle. But, one still wants maximum performance, excellent ammunition availability, and reasonable cost. To that end, I would suggest either a .270 Win or a .30-06 Sprg. Too, I would suggest that you save even more money, and get at handloads as soon as you can.
Let us know what you purchase, and as we say here: "No picture? It didn't happen!" We like photos.
Geno