first things first... get a volquartsen target hammer... You'll be glad you did :P They take take trigger down to ~2.5lbs just by dropping it in, and they're so much nicer than stock, you'll think you're shooting a different gun.
As for bolt buffers, weaponkraft makes probably the best ones... if it ever wears out, send it right back and he'll give you another :P Main purpose of these is if you use high-hyper velocity rounds (the bolt actually *hits* the stop pin) they'll stop the pin from warping/cracking the receiver.
Advice on barrels: for something inexpensive and very nice shooting, get a green mountain barrel... tapered or fluted is nice, and I hear they've created a few cool new styles too, including hexagonal...
If you want a light one, try the whistle pig aluminum sleeved/fluted/compensated bull barrel... they're really lightweight and pretty accurate to boot.
With any of this, keep in mind that accuracy (with a 10/22, at the very least) is the result of a full system of components... good trigger with fixed creep, a decent scope with adjustable objective, a decent barrel that's fitted correctly, possibly even headspaced, and a good ammo selection are all necessary if you want to really hit the mark. (winchester dynapoints rock in just about any 10/22 and can be purchased in bulk 500 pack for $10 at wal mart
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