I would like a list of the most accurate 0.177" air driven pellet guns
available for purchase new in the U.S. for less than $200.  Accuracy
of these guns is usually expressed as the "center to center" width in
inches of a pattern of 3 or 5 shots from 10 yards or meters.  A good
description of the way accuracy is defined is provided at
http://pyramydair.com/site/articles/accuracy/.  Thanks!

Check out OnPoint Firearms: 
http://www.onpointfirearms.com
They have Gamo, Crosman, Walther, and others.  I got my Gamo Delta
from them.  Fast shipping and good service. :)

If you set a price then we have to know a few things.  Does this
include a scope?  Rings?  Mounts?  How about a cleaning kit?  .177
cleaning rods are not available at WalMart.  Let me also say that each
individual gun will prefer a specific pellet.  No two guns are the
same.  Therefore you should plan on purchasing a sampler kit of
pellets.  Also, if you want to use a scope, you must buy one that is
specifically engineered for air guns.  The recoil is opposite that of
powder fired guns.  If I were you, I would go to airgun express and
look for a Beeman package deal and order yourself the sampler kit of
pellets.  Do not depend on velocity claims by the manufacturers.  And
before you buy a GAMO, try their triggers.  They are pathetic.  Good
luck.

Thanks for the help, tugtug.  

I'm willing to spring $200 for the gun itself, and already have a good
scope, pellet trap, cleaning kit, benchrest and a big selection of
pellets.  I arrived at the decision that I needed to ask for help
after being disappointed with the performance of a Gamo Sporter500. 
The trigger does suck, but that I could probably put up with. 
However, no matter what I tried, it shot 3/4" ctc groups at 30ft.  I
finally sent it back to the factory, where they immediately and
courteously replaced the gun with a new one of the same model, but at
least with open sights it's no better than the last one. Any advice
for a nice accurate single pump rifle would be greatly appreciated.