Texas hold 'em starting hands
There are 1326 distinct possible combinations of two hole cards from a standard 52-card deck in hold 'em, but since suits have no absolute value in this poker variant, many of these hands are identical in value before the flop. For example, and are identical in value, because each is a hand consisting of an ace and a jack of the same suit. Therefore, there are 169 non-equivalent starting hands in hold 'em, which is the total count of 13 pocket pairs, 13 × 12 / 2 = 78 suited hands and 78 unsuited hands (13 + 78 + 78 = 169). These 169 hands are "not" equally likely. Hold 'em hands are sometimes classified as having one of three "shapes":
Alternative means of making this calculation
First Step 
As confirmed above. There are 1326 possible combination of opening hand. Second Step
There are 6 different combos of each pair. 9h9c, 9h9s, 9h9d, 9c9s, 9c9d, 9d9s. Therefore, there are 78 possible combinations of pocket pairs (6 multiplied by 13 i.e. 22-AA)
To calculate the odds of being dealt a pair
78 (the number of any particular pair being dealt. As above) divided by 1326 (possible opening hands)
78/1326 = 0.058 or 5.8%
Probability of first card is 1.0 (any of the 52 cards)
Probability of second hand suit matching the first:
There are 13 cards per suit, and one is in your hand leaving 12 remaining of the 51 cards remaining in the deck. 12/51=.2353 or 23.5%
Offsuit pairs = 78
Other offsuit hands = 936
It is typical to abbreviate suited hands in hold 'em by affixing an "s" to the hand, as well as to abbreviate non-suited hands with an "o" (for offsuit). That is,
QQ represents any pair of queens,
KQ represents any king and queen,
AKo represents any ace and king of different suits, and
JTs represents any jack and ten of the same suit. Some notable theorists and players have created systems to rank the value of starting hands in limit Texas hold'em. These rankings do not apply to no limit play. David Sklansky and Mason Malmuth assigned in 1999 each hand to a group, and proposed all hands in the group could normally be played similarly. Stronger starting hands are identified by a lower number. Hands without a number are the weakest starting hands. As a general rule, books on Texas hold'em present hand strengths starting with the assumption of a nine or ten person table. The table below illustrates the concept: The "Chen Formula" is a way to compute the "power ratings" of starting hands that was originally developed by Bill Chen.
Highest Card
Based on the highest card, assign points as follows: 
Ace = 10 points, K = 8 points, Q = 7 points, J = 6 points. 10 through 2, half of face value (10 = 5 points, 9 = 4.5 points, etc.)
Pairs
For pairs, multiply the points by 2 (AA=20, KK=16, etc.), with a minimum of 5 points for any pair. 55 is given an extra point (i.e., 6). Suited
Add 2 points for suited cards. Closeness
Subtract 1 point for 1 gappers (AQ, J9)
2 points for 2 gappers (J8, AJ). 4 points for 3 gappers (J7, 73). 5 points for larger gappers, including A2 A3 A4
Add an extra point if connected or 1-gap and your highest card is lower than Q (since you then can make all higher straights) Phil Hellmuth's "Play Poker Like the Pros" book published in 2003. Statistics based on real play with their associated actual value in real bets. In poker communities, it is common for hole cards to be given nicknames. While most combinations have a nickname, stronger handed nicknames are generally more recognized, the most notable probably being the "Big Slick" - Ace and King of the same suit, although an Ace-King of any suit combination is less occasionally referred to as an Anna Kournikova, derived from the initials AK and because it "looks really good but rarely wins." Hands can be named according to their shapes (e.g., paired aces look like "rockets", paired jacks look like "fish hooks"); a historic event (e.g., A's and 8's - dead man's hand, representing the hand held by Wild Bill Hickok when he was fatally shot in the back by Jack McCall in 1876); many other reasons like animal names, alliteration and rhyming are also used in nicknames.
Essentials
In Texas hold 'em, a starting hand consists of two hole cards, which belong solely to the player and remain hidden from the other players. Unless otherwise specified, here the term "hand" applies to the player's two hole cards, or "starting hand".