Personally if I was just wanting a 500yd deer rifle I'd go 243. Rifle would depend on the target weight I was looking at. If I wanted heavy I'd pick up a Rem VLS and run either 105Amax's/VLD's, or run the 95VLD if the 105's wouldn't shoot. Scope would a 1" 3.5-10x40 Leupold with a M1 turret. If I wanted light I would try and find one of the special run Rem Mountain Guides in 243. They are a mountain rifle contour in a B&C TI stock. Scope/bullets would be the same. If I couldn't find one of those I'd snag up just an ADL 243 and put it in a B&C TI stock.
I've been full circle with rifle builds over the past 6 years or so since I got into this. I went through the "heavy" rifle stage and have finally ended up with light to modest weight rifles that wear good tubes and good triggers. I kind of feel that a quality tube is a quality tube and that matter more than what the outside diameter measures, at least for me.
I have a couple of the 243 mountain guides mentioned above and here is one of them. This was before I punched it to 243AI and it wears a fixed 6x scope. This group was shot at 500yds right at the end of the day, off of a pack for a rest while laying prone. Pretty much a mirror of hunting conditions. Now the group wouldn't make a benchrester happy, but as far as a pure killing rilfe.....there's nothing more I'd ask of it. This rifle weighs 6#13oz all up and is a joy to carry and easy to shoot.