For your 1st deer rifle???? Why buy one and then upgrade later when the cost is going to be the same? 243 and 7-08 would work fine for deer but neither will have the energy of the 270. Besides, someday you might get a chance to do a little elk hunting. You have had some experience with the 270 and found it to be pleasant, so my advice it to go with it. By the way, bullet placement is important and I love all these quotes and such that game can be brought down at long distances with small caliber rifles, but down range energy is important too. You can bring down a bear at 200 yds with a 22lr if you hit him in the eye and go into the brain. You can bring down elephant with a 7x57. However, they would not be the best choice. You will be hard pressed to find anything better suited for deer at the range you stated than the 270.
No such thing as a stupid question. What is stupid is not asking it.