IMHO the best bang-for-the-buck is the 40 grain high velocity Federal Champion (in the blue box). I bought a bunch of them recently in Brick form for $20.99 for a Brick of 500. They are accurate, RELIABLE and come in boxes of 50 rounds packed in nice little plastic trays inside the box.
The WORST EVER is Remington Thunderbolt! PURE GARBAGE!! In fact I shy away from ALL REMINGTON ammo these days as I feel it is the worst ammo currently made in the USA. I have even had FTF with their centerfire ammo which I have never experienced with the other major brand.
Winchester Wildcats are somewhere in the middle, but not bad when purchased on sale. A few dud's here and there, but OK for plinking.
CCI ammo is good but always seems more expensive than the other stuff.
I recently tried the Federal Bulk Pack made for Auto Loaders (believe its about 350 rounds in a "milk container") and it does seem to work quite well.
Be careful when you buy Bricks, because some of them are now packed 400 (American eagle is one) to a Brick instead of the traditional 500 rounds. Some brands have also dropped the weight to 36 or 38 grains to save a few pennies as well, so READ THE LABEL BEFORE going to the check out line. Ask me how I know!
Chief38