You'll probably get a bunch of different perspectives as the thread grows. These perspectives are related to how they play.
Opening preflop is a major one imho. Some people say the amount should be related to position, others that it should be always the same. My personal view is that when I first sit my opening will be 4BB. If the table is too loose, if there are a number of limpers, etc, I'll adapt, but I will not change the 4BB raise depending on what my hand is, ever!
Post flop betting should be based on % of the pot. What that % is depends on a number of factors. I for once always bet 1/2 of the pot unless I want to make runners pay for their draws where I'll bet full pot. I'm considering 2/3 as my base bet though. In the river I either shove or bet full pot for value (depending on the villain) or make a blocker bet of 1/4 of the pot. I'm pretty sure my river tactics won't work on higher stakes though.
One of the things is that I'm extremely consistent. I use the same percentages in the same situations for either value or fold. I'm not sure if this is the correct thing to do, but it's working at the moment.