I was in the same boat as you, with the exception that I have a few M14/M1A types already.
I started out looking at bolt action rifles like the Ruger GSR, but ended up going with their SR762 instead.
It utilizes a 2 stage adjustable piston gas system, and I'm happy with it so far.
The GSR costs roughly half as much as the SR762, but I prefer semiautomatics over bolt actions for use as an all around rifle.
The SR762 weighs in at 8.6 lbs with an OAL of 34.75 inches out to 38 inches depending on where you like to adjust the 6 position adjustable stock. ( Not too bad considering that it sports a med weight fluted bbl.)
The GSR weighs out at around 1 lbs less in weight, and has an adjustable spacer type laminate stock.
While both have 1-10 twist 16in tubes with threaded muzzles, the SR762 barrel is chrome lined, as well as the piston, chamber and BCG.
I also preferred the iron sights that came with the SR, and the rifle sold with 3 20rd mags, front sight adjustment tool, Houge pistol grip, 2 sections of rail, 3 rubber hg grip covers, and a decent little soft case.
The SR sports a monolithic flat top upper, so optics mounting is easy, versatile, and wont interfere with the rear sight assembly, as it folds down out of the way along with the front sight assembly. ( I don't have a need for rails at the 3/6/9 0clock position, and like the design of the handguard. The 2 sections of rail that come with it is a nice feature if one does have the need however.)
The SR762 is super simple and easy to clean. ( I wont go back to a DGI system again.....lol) Then again, the GSR aint all that complicated to maintain either.
Things I don't much care for:
The flash hider is about useless, and it's only nice feature is that it protects the rifle's threads as well as the crown from possible damage. It appears that the GSR utilizes the same type.
It's black. (Not a big fan of the E.B.R. club)
The trigger could have been a tad better out of the box, but it is getting better now that I have used it. ( 220rds along with dry fire drills.)
Unlike my M14's, this one may be hard to get certain spare parts for.
Just like M14 spare parts, I typically turn them into "spare" rifles..... so if this rifle turns out to be a keeper, I'll most likely buy another...... or in this case......another complete upper when Ruger gets around to selling them as they did with their SR556.
The lower receiver uses commonly found components as far as I can tell at this time.
FWIW......... I don't plan on getting into gun fights with any personally owned firearms, but if no other alternative presented itself...... I would much rather have a magazine fed semiautomatic rifle over any other type out there.
Another FWIW here, but if you really want an AR10 type, then get one. I tried to settle for less in the past, but it just aint worth it. Get what you really want the first time.
Mine(SR762) ran quite a bit less than $2500 NIB, so you should have around 750 bucks left over to spend on optics, rings, a sling, and a decent muzzle brake or flash hider.
http://www.ruger.com/products/sr762/features.html#