I realized today that everybody in my gaming group, both in the game I play in and in the game I run, have been handicapping ourselves on hit points. Myself included. After installing the D&D official character builder, I noticed when I was done that the character sheets had a lot more HP on them then I'd expected. My gnome sorceror was sitting up at a fat 25 hit points. I figured it was more likely that I made a mistake then it was that the software had made a mistake. So I grabbed the PHB, and looked it up. Turns out that your starting hit points are whatever number they are for your class, plus your Constitution score, not your Con modifier. Whoops! So instead of having 13 hit points, my gnome had 25.
For those who complain that 4th ed made things too easy, I'm sure this will be one more thing to dislike, but for those of us who didn't like being a starting sorcerer with 4 hit points, it's quite a pleasant change. This early 1st level bonanza of hit points is offset by the fact that, when you level, you only gain a set number of hit points, and it's not a high number.
Fighters are a good way to illustrate this, as they traditionally have high points. In 4th ed, a fighter gets 15 hit points at creation, plus his constitution score. 16 is a pretty standard con score for fighters. So, 15+16, 31 hit points at level 1. But they only get to add 6 hit points per level they gain. So, to illustrate:
2nd level: 37
3rd level: 43
4th level: 49
5th level: 55
Comparing that to 3rd edition (or 3.5), a fighter got 1d10 at start, plus their constitution modifier. And at each level, they added 1d10 + con mod. So, using the same fighter's stats (16 con, for a modifier of +3) as an example, and the d10 I keep in my desk at work, you get the following:
1st level: rolled a 9, add the con mod of 3 and you get 12
2nd level: rolled a 4, goes up to 19
3rd level: rolled an 8, total is 30
4th level: rolled 6, total 39
5th level: rolled 10, total 52
At 5th level, they're pretty even. Within 3 HP of each other. Let's take it out to 10th level.
6th level: 61
7th level: 68
8th level: 74
9th level: 80
10th level: 86
3rd ed (rolling a d10 and adding 3, yes I rolled high with some frequency)
6th level: 56
7th level: 67
8th level: 80
9th level: 92
10th level: 101
Under 4th ed, you will have 86 hit points at 10, as a fighter with 16 constitution. No more, no less. Under 3rd ed, you can have as low as 40 hit points at level 10, in the unlikely event that you roll 1 ten times in a row, or you can have as many as 130 hit points at tenth level. The midpoint between the two extremes comes out to 85 hit points. Seeing this, I find it rather reassuring, as it is a sign that they really did look pretty deeply into the stuff they added. They took a lot of the more random elements out, with regard to leveling, and I think everything scales better as a result.