Well, in a game like Texas Hold'em, the worst two-card "starting hand" is 2-7 offsuit. The best starting hand is a Pair of Aces (AA).
Like Chris already mentioned, the worst five card hand is something like;
A-2-10-7-Q - high card only with a mix of suits. From there, the order of poker hands goes;
- One Pair
- Two Pair
- Three-of-a-kind
- Straight
- Flush
- Full House
- Four-of-a-kind
- Straight Flush
- Royal Flush