Lots of good advice here. The "best long range rifle" is probably some $10k monster with a Khales on top, so I'll pretend you asked for the best long range rifle bang for the buck (plus I'm kind of cheap, so this is more my speed). If I was planning on getting into longer range PRS style shooting on the cheap-ish, I would opt for one of two different rifles, either a Ruger Precision Rifle, or a Tikka CTR 24", both in 6.5 Creedmoor. The 6.5 is probably the best out of the box learning option out there right now, lots of very good heavy bullet factory ammo. When you do start reloading, it's cheaper to reload higher BC 6.5 than it is higher BC .308 loads, at least it is for me (bullets are the largest cost, and lighter is generally cheaper).
For a scope I'd get (and have gotten) an SWFA SS. If you're ok with a fixed power, the 10x and 12x mil/mil's are excellent. I use the 12x on my .308, and like that it's enough magnification for shooting steel out to 850, but not so much that I can't find 2" swingers at 200 and 300 yds under time pressure. I also like the SWFA 3-15 FFP mil/mil for a variable, but honestly when I'm shooting our local range matches here, I usually just leave it on 12x... the option is there to turn it up when taking things slower though. The variable does run $699 vs the very reasonable $299 for the fixed scopes. The SWFA's aren't going to compare optically with the Razor's, Nightforces, USO, Khales, etc. but they are a lot cheaper, and are repeatable, which is what's most important. I personally use SWFA rings as well, although I'm sure plenty of folks would not be willing to take the chance on $50 rings, I've had no problems.
Of course, it probably wouldn't be a bad idea to just pick up a nice faster twist .223 and get some cheap range time in. In the context of your question though, in the $1,350 to $1,750 range I think you'd be hard pressed to beat one of the setups listed above. If money is no object, of course there is no shortage of nicer, better options out there.
Edit: Didn't see that you had set a $3k price ceiling.