I've got Model 700's in .243, .30-06 and 7mm Rem. Mag. I used the .30-06 for deer hunting until a couple years ago, then switched to the .243. I hunt in the Hill Country northwest of San Antonio, and have gotten great performance out of my .243. The deer don't seem to go a bit farther after the shot than they did with my 06.

The .270 and the .30-06 will both perform well on deer and varmints (although they are definitely "overkill" for varmints...). Based upon walking up and down the line at the shooting range a few times, I think the .270 might be slightly more popular in Texas.

If, like most of us in Texas, you plan to hunt out of a blind, I'd definitely consider a "short action" cartridge. Even that inch difference will make manuevering the rifle into shooting position easier. If you are looking for something a little more potent than a .243, I'd seriously give the 7mm-08 a look.