I agree with most, if not all, of the above. Here's the route I took...

Started with a 700 in .308. I shot about 1400 rounds through it (all hand/reloads). Durring that time I attended an outstanding course where I was able to see the limits of the rifle and caliber, and a few of the Prarie Dog matches mentioned. At every opportunity, I got behind other rifles and scopes and tried them out. Most of the long range community is very friendly and will be glad to help you out.

After trying plently of combinations I determined what would work best for my requirements. Since then, I've moved up to a Nightforce Scope, had a Manners stock built to my specs, ordered a match grade barrel, and a custom action. I'm still waiting on the action and barrel. Eventually, it will all make its way to TJs gunsmithing in Aurora. It'll be a 260 Rem.

Here's my advice (which may be a bit redundant)
1) Further identify your requirements - What do I want the rilfe to do? What do I not need? What would be nice? - Think about, distance, target vs hunting, size, weight, etc...
2) Choose a caliber based on the bullets you want to shoot. If you are a reloader, then you have a lot more flexibility in caliber choice.
3) Try as much as possible before buying anything
4) Get a good scope the first time. Nightforce is a good starting point, and used NXS' can be had for around $1200.
5) If you are unsure of your requirements, start with a relatively cheap 700 in .308. You can always sell it and move up. Or build a custom gun on the action...
6) Don't forget about suppressors. Once you shoot one, or shoot next to one, you'll be hooked. They are simply amazing on bolt guns.

Good luck.