DO NOT MAKE THE FOLLOWING THE FIRST BOOK(S) YOU READ:
a. Theory of Poker (or ANY Sklanksy/Malmuth for that matter)
b. Harrington on Holdem 1-3
c. Weighing the Odds in Holdem Poker by King Yao
d. Super System I or II
unless you have one (or more) of the following:
1. you are already an experienced player
2. you have a mathematical and/or statistical background of some sort
3. you have decent or recent academic training and/or are used to rigorous study of texts in some manner.
You will, of course, want [a, b, c, d above] and more eventually, they just are not beginners books.
I would say to read some of Phil Gordon's or John Vorhaus's books before if you are a beginner(and I would say the majority of players online are)
For SNGs, you should read Colin Moshman Sit 'n Go Strategy.
For MTTs, the 3 "Harrington on Holdem" books.
For cash games, you could start with the 2 "Harrington on Cash Games" books, then Ed Miller's ebook if you ever get to the relevant stakes (i.e. 200nl)
I would strongly recommend Paul Kammen's HowTo Beat Low-Limit 7-Card Stud Poker. This book builds a tight/agressive level mentality, strong base of play. I give my gracious thanx to Kammen for composing a manuel of superior mechanics. To this day, majority of my 7 card stud earnings are due to the strategic issues tought here. A perfect 10.0 on the richter scale. Enjoy!
Have you read Sklansky's book on 7 card stud? I heard this was a good book to read.
Does Kammen's book cover any variations of stud like hi/lo?