ANACS (American Numismatics Association Certification Service)
ICG (Independent Coin Grading)
PCGS (PROFESSIONAL COIN GRADING SERVICE)
NGC (NUMISMATICS GUARANTEE CORPORATION)
NGC Numismatics Guarantee Corporation (Recommended)
Considered the second top grading company all across the board. However, many consider NGC on par with PCGS. I feel the NGC holders lack in eye appeal compared to PCGS, but you can't argue their grading standard. They also have a knew "side view" slab so you can see the edge of a graded coin. NGC Web Site
(Recommended)
I feel they are just as good as NGC and PCGS for grading, quality, attribution and authentication. Will grade problem coins. They claim to be the first coin grading company created by the American Numismatic Association (ANA) in 1972. The holders where flat, plastic type with a certificate and a picture for the grade of the obverse and reverse of each coin.
Since 1989 they slab their coins in the hard plastic holder made popular by PCGS.
ANACS Web Site
(Recommended)
A top notch grading company on the conservative side with PCGS, NGC, ANACS, etc. They have new holders where one can view the side of the coin and their holders do have eye appeal. ICG Web site
Old "Rattler" Green Label (Recommended)
Oldest PCGS Holder from the first few years. It is called a "Rattler" holder because the slab can be shook causing the coin to knock against the holder. The darker green holder replaced this slab version because of the coin movement.
Old Green Label (Recommended)
Many feel these holders contain undergraded coins and collectors buy them with the hope they can re-submit and attain a higher grade.
PCGS Professional Coin Grading Service (Recommended)

Considered the top grading company all across the board. Many dealers will buy coins graded by PCGS, "site unseen". They claim to be the first grading company, but are definetly the first to use hard plastic holders. It is widely accepted that the Old Green and Old "Rattler" holders where the more conservative years for PCGS grading. Many buyers pay a higher premium for coins in these holders, hoping for a higher grade upon re-submission with the  less conservative standards of today.

Aug. 30, 2007 update: PCGS will no longer use First Strike on their holders unless it can be proven that the coins where struck by the first die pair.

PCGS Web Site
More information on the different generation PCGS Holders and fake slabs. PCGS Slabs...
WARNING *NEW*
FAKE NGC coin holders have been reported. You can see a difference in the letter and number font, and the label is a bit off-center. The most alarming aspect is that the makers of these slabs are researching real NGC certification numbers, typing them onto these fake labels, then putting a fake coin in the holder. Read More
FEATURED STORY
Ebay's new third party grading company policy allows the following grading companies: PCGS, NCS, ICG, ANACS AND NGC.
Read More
Ebay Policy Allows Four Grading Services Only

Ebay has a new policy on selling graded coins. The Third Party Grading Companies that are allowed on ebay are-PCGS, NGC, ICG, ANACS. NCS is also allowed, but is a subdivision of NGC which is a Conservation Holder. For more information on NCS click the here. This new coin auction policy was enacted due the wide-spread "Coin Slabbing" frauds on ebay, and people who self grade raw coins in order to hype their listings for higher bids. I encourage all who see an auction that violates this policy to report them to ebay. Report Ebay Listing Violations. There are other provisions in this policy. For example, the auction title cannot include a numerical grade like MS65, VF30, etc. Read an ebay thread on this policy by clicking the link below in our Featured Story.
CoinHELP!®
Ebay Daily Deals